diff --git a/be_misc.c b/be_misc.c
index 9fcfec55..4774bd70 100644
--- a/be_misc.c
+++ b/be_misc.c
@@ -9,7 +9,7 @@
 #include "putty.h"
 #include "network.h"
 
-void backend_socket_log(void *frontend, int type, SockAddr addr, int port,
+void backend_socket_log(Frontend *frontend, int type, SockAddr addr, int port,
                         const char *error_msg, int error_code, Conf *conf,
                         int session_started)
 {
diff --git a/callback.c b/callback.c
index 10f923d0..0a05f624 100644
--- a/callback.c
+++ b/callback.c
@@ -17,13 +17,13 @@ struct callback {
 struct callback *cbcurr = NULL, *cbhead = NULL, *cbtail = NULL;
 
 toplevel_callback_notify_fn_t notify_frontend = NULL;
-void *frontend = NULL;
+void *notify_ctx = NULL;
 
 void request_callback_notifications(toplevel_callback_notify_fn_t fn,
-                                    void *fr)
+                                    void *ctx)
 {
     notify_frontend = fn;
-    frontend = fr;
+    notify_ctx = ctx;
 }
 
 static void run_idempotent_callback(void *ctx)
@@ -87,7 +87,7 @@ void queue_toplevel_callback(toplevel_callback_fn_t fn, void *ctx)
      * callback keeps re-scheduling itself.
      */
     if (notify_frontend && !cbhead && !cbcurr)
-        notify_frontend(frontend);
+        notify_frontend(notify_ctx);
 
     if (cbtail)
         cbtail->next = cb;
diff --git a/defs.h b/defs.h
index 43f56dfe..53ded962 100644
--- a/defs.h
+++ b/defs.h
@@ -49,6 +49,8 @@ typedef struct Backend_vtable Backend_vtable;
 typedef struct Ldisc_tag Ldisc;
 typedef struct LogContext_tag LogContext;
 
+typedef struct Frontend Frontend;
+
 typedef struct ssh_tag *Ssh;
 
 /* Note indirection: for historical reasons (it used to be closer to
diff --git a/fuzzterm.c b/fuzzterm.c
index cdefb0d9..fda9f6c8 100644
--- a/fuzzterm.c
+++ b/fuzzterm.c
@@ -38,12 +38,12 @@ int main(int argc, char **argv)
 	return 0;
 }
 
-int from_backend(void *frontend, int is_stderr, const void *data, int len)
+int from_backend(Frontend *frontend, int is_stderr, const void *data, int len)
 { return 0; }
 
 /* functions required by terminal.c */
 
-void request_resize(void *frontend, int x, int y) { }
+void request_resize(Frontend *frontend, int x, int y) { }
 void do_text(Context ctx, int x, int y, wchar_t * text, int len,
 	     unsigned long attr, int lattr, truecolour tc)
 {
@@ -67,40 +67,40 @@ void do_cursor(Context ctx, int x, int y, wchar_t * text, int len,
     printf("\n");
 }
 int char_width(Context ctx, int uc) { return 1; }
-void set_title(void *frontend, char *t) { }
-void set_icon(void *frontend, char *t) { }
-void set_sbar(void *frontend, int a, int b, int c) { }
+void set_title(Frontend *frontend, char *t) { }
+void set_icon(Frontend *frontend, char *t) { }
+void set_sbar(Frontend *frontend, int a, int b, int c) { }
 
 void ldisc_send(Ldisc *ldisc, const void *buf, int len, int interactive) {}
 void ldisc_echoedit_update(Ldisc *ldisc) {}
-Context get_ctx(void *frontend) { 
+Context get_ctx(Frontend *frontend) { 
     static char x;
 
     return &x;
 }
 void free_ctx(Context ctx) { }
-void palette_set(void *frontend, int a, int b, int c, int d) { }
-void palette_reset(void *frontend) { }
-int palette_get(void *frontend, int n, int *r, int *g, int *b) {return FALSE;}
-void write_clip(void *frontend, int clipboard,
+void palette_set(Frontend *frontend, int a, int b, int c, int d) { }
+void palette_reset(Frontend *frontend) { }
+int palette_get(Frontend *frontend, int n, int *r, int *g, int *b) {return FALSE;}
+void write_clip(Frontend *frontend, int clipboard,
                 wchar_t *a, int *b, truecolour *c, int d, int e) { }
-void set_raw_mouse_mode(void *frontend, int m) { }
-void frontend_request_paste(void *frontend, int clipboard) { }
-void do_beep(void *frontend, int a) { }
-void sys_cursor(void *frontend, int x, int y) { }
+void set_raw_mouse_mode(Frontend *frontend, int m) { }
+void frontend_request_paste(Frontend *frontend, int clipboard) { }
+void do_beep(Frontend *frontend, int a) { }
+void sys_cursor(Frontend *frontend, int x, int y) { }
 void modalfatalbox(const char *fmt, ...) { exit(0); }
 void nonfatal(const char *fmt, ...) { }
 
-void set_iconic(void *frontend, int iconic) { }
-void move_window(void *frontend, int x, int y) { }
-void set_zorder(void *frontend, int top) { }
-void refresh_window(void *frontend) { }
-void set_zoomed(void *frontend, int zoomed) { }
-int is_iconic(void *frontend) { return 0; }
-void get_window_pos(void *frontend, int *x, int *y) { *x = 0; *y = 0; }
-void get_window_pixels(void *frontend, int *x, int *y) { *x = 0; *y = 0; }
-char *get_window_title(void *frontend, int icon) { return "moo"; }
-int frontend_is_utf8(void *frontend) { return TRUE; }
+void set_iconic(Frontend *frontend, int iconic) { }
+void move_window(Frontend *frontend, int x, int y) { }
+void set_zorder(Frontend *frontend, int top) { }
+void refresh_window(Frontend *frontend) { }
+void set_zoomed(Frontend *frontend, int zoomed) { }
+int is_iconic(Frontend *frontend) { return 0; }
+void get_window_pos(Frontend *frontend, int *x, int *y) { *x = 0; *y = 0; }
+void get_window_pixels(Frontend *frontend, int *x, int *y) { *x = 0; *y = 0; }
+char *get_window_title(Frontend *frontend, int icon) { return "moo"; }
+int frontend_is_utf8(Frontend *frontend) { return TRUE; }
 
 /* needed by timing.c */
 void timer_change_notify(unsigned long next) { }
@@ -142,8 +142,8 @@ int dlg_coloursel_results(union control *ctrl, void *dlg,
 void dlg_refresh(union control *ctrl, void *dlg) { }
 
 /* miscellany */
-void logevent(void *frontend, const char *msg) { }
-int askappend(void *frontend, Filename *filename,
+void logevent(Frontend *frontend, const char *msg) { }
+int askappend(Frontend *frontend, Filename *filename,
 	      void (*callback)(void *ctx, int result), void *ctx) { return 0; }
 
 const char *const appname = "FuZZterm";
diff --git a/ldisc.c b/ldisc.c
index 3596ea63..e17b13c7 100644
--- a/ldisc.c
+++ b/ldisc.c
@@ -78,7 +78,7 @@ static void bsb(Ldisc *ldisc, int n)
 #define KCTRL(x) ((x^'@') | 0x100)
 
 Ldisc *ldisc_create(Conf *conf, Terminal *term,
-                   Backend *backend, void *frontend)
+                    Backend *backend, Frontend *frontend)
 {
     Ldisc *ldisc = snew(Ldisc);
 
diff --git a/ldisc.h b/ldisc.h
index af7afde3..e3d043b5 100644
--- a/ldisc.h
+++ b/ldisc.h
@@ -11,7 +11,7 @@
 struct Ldisc_tag {
     Terminal *term;
     Backend *backend;
-    void *frontend;
+    Frontend *frontend;
 
     /*
      * Values cached out of conf.
diff --git a/logging.c b/logging.c
index 75c457e3..b1fb638b 100644
--- a/logging.c
+++ b/logging.c
@@ -17,7 +17,7 @@ struct LogContext_tag {
     enum { L_CLOSED, L_OPENING, L_OPEN, L_ERROR } state;
     bufchain queue;
     Filename *currlogfilename;
-    void *frontend;
+    Frontend *frontend;
     Conf *conf;
     int logtype;		       /* cached out of conf */
 };
@@ -367,7 +367,7 @@ void log_packet(LogContext *ctx, int direction, int type,
     logflush(ctx);
 }
 
-LogContext *log_init(void *frontend, Conf *conf)
+LogContext *log_init(Frontend *frontend, Conf *conf)
 {
     LogContext *ctx = snew(LogContext);
     ctx->lgfp = NULL;
diff --git a/misc.c b/misc.c
index 92890322..fdd5635c 100644
--- a/misc.c
+++ b/misc.c
@@ -216,7 +216,7 @@ char *host_strduptrim(const char *s)
     return dupstr(s);
 }
 
-prompts_t *new_prompts(void *frontend)
+prompts_t *new_prompts(Frontend *frontend)
 {
     prompts_t *p = snew(prompts_t);
     p->prompts = NULL;
diff --git a/network.h b/network.h
index 9914ce34..79f44f5e 100644
--- a/network.h
+++ b/network.h
@@ -95,7 +95,8 @@ Socket new_connection(SockAddr addr, const char *hostname,
 Socket new_listener(const char *srcaddr, int port, Plug plug,
                     int local_host_only, Conf *conf, int addressfamily);
 SockAddr name_lookup(const char *host, int port, char **canonicalname,
-		     Conf *conf, int addressfamily, void *frontend_for_logging,
+                     Conf *conf, int addressfamily,
+                     Frontend *frontend_for_logging,
                      const char *lookup_reason_for_logging);
 int proxy_for_destination (SockAddr addr, const char *hostname, int port,
                            Conf *conf);
@@ -221,7 +222,7 @@ extern Plug nullplug;
 /*
  * Exports from be_misc.c.
  */
-void backend_socket_log(void *frontend, int type, SockAddr addr, int port,
+void backend_socket_log(Frontend *frontend, int type, SockAddr addr, int port,
                         const char *error_msg, int error_code, Conf *conf,
                         int session_started);
 void log_proxy_stderr(Plug plug, bufchain *buf, const void *vdata, int len);
diff --git a/proxy.c b/proxy.c
index 6ccd4025..f55973fc 100644
--- a/proxy.c
+++ b/proxy.c
@@ -368,7 +368,7 @@ static char *dns_log_msg(const char *host, int addressfamily,
 }
 
 SockAddr name_lookup(const char *host, int port, char **canonicalname,
-		     Conf *conf, int addressfamily, void *frontend,
+                     Conf *conf, int addressfamily, Frontend *frontend,
                      const char *reason)
 {
     char *logmsg;
diff --git a/pscp.c b/pscp.c
index 854e6815..594f119f 100644
--- a/pscp.c
+++ b/pscp.c
@@ -118,7 +118,7 @@ void nonfatal(const char *fmt, ...)
     sfree(str2);
     errs++;
 }
-void connection_fatal(void *frontend, const char *fmt, ...)
+void connection_fatal(Frontend *frontend, const char *fmt, ...)
 {
     char *str, *str2;
     va_list ap;
@@ -157,7 +157,8 @@ static unsigned char *outptr;	       /* where to put the data */
 static unsigned outlen;		       /* how much data required */
 static unsigned char *pending = NULL;  /* any spare data */
 static unsigned pendlen = 0, pendsize = 0;	/* length and phys. size of buffer */
-int from_backend(void *frontend, int is_stderr, const void *data, int datalen)
+int from_backend(Frontend *frontend, int is_stderr,
+                 const void *data, int datalen)
 {
     unsigned char *p = (unsigned char *) data;
     unsigned len = (unsigned) datalen;
@@ -195,7 +196,7 @@ int from_backend(void *frontend, int is_stderr, const void *data, int datalen)
 
     return 0;
 }
-int from_backend_untrusted(void *frontend_handle, const void *data, int len)
+int from_backend_untrusted(Frontend *frontend, const void *data, int len)
 {
     /*
      * No "untrusted" output should get here (the way the code is
@@ -204,7 +205,7 @@ int from_backend_untrusted(void *frontend_handle, const void *data, int len)
     assert(!"Unexpected call to from_backend_untrusted()");
     return 0; /* not reached */
 }
-int from_backend_eof(void *frontend)
+int from_backend_eof(Frontend *frontend)
 {
     /*
      * We usually expect to be the party deciding when to close the
diff --git a/psftp.c b/psftp.c
index c2d23832..d57b118e 100644
--- a/psftp.c
+++ b/psftp.c
@@ -2466,7 +2466,7 @@ void nonfatal(const char *fmt, ...)
     fputs(str2, stderr);
     sfree(str2);
 }
-void connection_fatal(void *frontend, const char *fmt, ...)
+void connection_fatal(Frontend *frontend, const char *fmt, ...)
 {
     char *str, *str2;
     va_list ap;
@@ -2506,7 +2506,8 @@ static unsigned char *outptr;	       /* where to put the data */
 static unsigned outlen;		       /* how much data required */
 static unsigned char *pending = NULL;  /* any spare data */
 static unsigned pendlen = 0, pendsize = 0;	/* length and phys. size of buffer */
-int from_backend(void *frontend, int is_stderr, const void *data, int datalen)
+int from_backend(Frontend *frontend, int is_stderr,
+                 const void *data, int datalen)
 {
     unsigned char *p = (unsigned char *) data;
     unsigned len = (unsigned) datalen;
@@ -2550,7 +2551,7 @@ int from_backend(void *frontend, int is_stderr, const void *data, int datalen)
 
     return 0;
 }
-int from_backend_untrusted(void *frontend_handle, const void *data, int len)
+int from_backend_untrusted(Frontend *frontend, const void *data, int len)
 {
     /*
      * No "untrusted" output should get here (the way the code is
@@ -2559,7 +2560,7 @@ int from_backend_untrusted(void *frontend_handle, const void *data, int len)
     assert(!"Unexpected call to from_backend_untrusted()");
     return 0; /* not reached */
 }
-int from_backend_eof(void *frontend)
+int from_backend_eof(Frontend *frontend)
 {
     /*
      * We expect to be the party deciding when to close the
diff --git a/putty.h b/putty.h
index 2f53d645..1a8c30ce 100644
--- a/putty.h
+++ b/putty.h
@@ -445,7 +445,7 @@ struct Backend {
     const Backend_vtable *vt;
 };
 struct Backend_vtable {
-    const char *(*init) (void *frontend_handle, Backend **backend_out,
+    const char *(*init) (Frontend *frontend, Backend **backend_out,
 			 Conf *conf, const char *host, int port,
                          char **realhost, int nodelay, int keepalive);
 
@@ -608,11 +608,11 @@ typedef struct {
     size_t n_prompts;   /* May be zero (in which case display the foregoing,
                          * if any, and return success) */
     prompt_t **prompts;
-    void *frontend;
+    Frontend *frontend;
     void *data;		/* slot for housekeeping data, managed by
 			 * get_userpass_input(); initially NULL */
 } prompts_t;
-prompts_t *new_prompts(void *frontend);
+prompts_t *new_prompts(Frontend *frontend);
 void add_prompt(prompts_t *p, char *promptstr, int echo);
 void prompt_set_result(prompt_t *pr, const char *newstr);
 void prompt_ensure_result_size(prompt_t *pr, int len);
@@ -673,7 +673,7 @@ enum { ALL_CLIPBOARDS(CLIP_ID) N_CLIPBOARDS };
 /*
  * Exports from the front end.
  */
-void request_resize(void *frontend, int, int);
+void request_resize(Frontend *frontend, int, int);
 void do_text(Context, int, int, wchar_t *, int, unsigned long, int,
              truecolour);
 void do_cursor(Context, int, int, wchar_t *, int, unsigned long, int,
@@ -682,46 +682,46 @@ int char_width(Context ctx, int uc);
 #ifdef OPTIMISE_SCROLL
 void do_scroll(Context, int, int, int);
 #endif
-void set_title(void *frontend, char *);
-void set_icon(void *frontend, char *);
-void set_sbar(void *frontend, int, int, int);
-Context get_ctx(void *frontend);
+void set_title(Frontend *frontend, char *);
+void set_icon(Frontend *frontend, char *);
+void set_sbar(Frontend *frontend, int, int, int);
+Context get_ctx(Frontend *frontend);
 void free_ctx(Context);
-void palette_set(void *frontend, int, int, int, int);
-void palette_reset(void *frontend);
-int palette_get(void *frontend, int n, int *r, int *g, int *b);
-void write_clip(void *frontend, int clipboard, wchar_t *, int *,
+void palette_set(Frontend *frontend, int, int, int, int);
+void palette_reset(Frontend *frontend);
+int palette_get(Frontend *frontend, int n, int *r, int *g, int *b);
+void write_clip(Frontend *frontend, int clipboard, wchar_t *, int *,
                 truecolour *, int, int);
-void optimised_move(void *frontend, int, int, int);
-void set_raw_mouse_mode(void *frontend, int);
-void connection_fatal(void *frontend, const char *, ...);
+void optimised_move(Frontend *frontend, int, int, int);
+void set_raw_mouse_mode(Frontend *frontend, int);
+void connection_fatal(Frontend *frontend, const char *, ...);
 void nonfatal(const char *, ...);
 void modalfatalbox(const char *, ...);
 #ifdef macintosh
 #pragma noreturn(modalfatalbox)
 #endif
-void do_beep(void *frontend, int);
-void begin_session(void *frontend);
-void sys_cursor(void *frontend, int x, int y);
-void frontend_request_paste(void *frontend, int clipboard);
-void frontend_keypress(void *frontend);
-void frontend_echoedit_update(void *frontend, int echo, int edit);
+void do_beep(Frontend *frontend, int);
+void begin_session(Frontend *frontend);
+void sys_cursor(Frontend *frontend, int x, int y);
+void frontend_request_paste(Frontend *frontend, int clipboard);
+void frontend_keypress(Frontend *frontend);
+void frontend_echoedit_update(Frontend *frontend, int echo, int edit);
 /* It's the backend's responsibility to invoke this at the start of a
  * connection, if necessary; it can also invoke it later if the set of
  * special commands changes. It does not need to invoke it at session
  * shutdown. */
-void update_specials_menu(void *frontend);
-int from_backend(void *frontend, int is_stderr, const void *data, int len);
-int from_backend_untrusted(void *frontend, const void *data, int len);
+void update_specials_menu(Frontend *frontend);
+int from_backend(Frontend *frontend, int is_stderr, const void *data, int len);
+int from_backend_untrusted(Frontend *frontend, const void *data, int len);
 /* Called when the back end wants to indicate that EOF has arrived on
  * the server-to-client stream. Returns FALSE to indicate that we
  * intend to keep the session open in the other direction, or TRUE to
  * indicate that if they're closing so are we. */
-int from_backend_eof(void *frontend);
-void notify_remote_exit(void *frontend);
+int from_backend_eof(Frontend *frontend);
+void notify_remote_exit(Frontend *frontend);
 /* Get a sensible value for a tty mode. NULL return = don't set.
  * Otherwise, returned value should be freed by caller. */
-char *get_ttymode(void *frontend, const char *mode);
+char *get_ttymode(Frontend *frontend, const char *mode);
 /*
  * >0 = `got all results, carry on'
  * 0  = `user cancelled' (FIXME distinguish "give up entirely" and "next auth"?)
@@ -730,15 +730,15 @@ char *get_ttymode(void *frontend, const char *mode);
 int get_userpass_input(prompts_t *p, bufchain *input);
 #define OPTIMISE_IS_SCROLL 1
 
-void set_iconic(void *frontend, int iconic);
-void move_window(void *frontend, int x, int y);
-void set_zorder(void *frontend, int top);
-void refresh_window(void *frontend);
-void set_zoomed(void *frontend, int zoomed);
-int is_iconic(void *frontend);
-void get_window_pos(void *frontend, int *x, int *y);
-void get_window_pixels(void *frontend, int *x, int *y);
-char *get_window_title(void *frontend, int icon);
+void set_iconic(Frontend *frontend, int iconic);
+void move_window(Frontend *frontend, int x, int y);
+void set_zorder(Frontend *frontend, int top);
+void refresh_window(Frontend *frontend);
+void set_zoomed(Frontend *frontend, int zoomed);
+int is_iconic(Frontend *frontend);
+void get_window_pos(Frontend *frontend, int *x, int *y);
+void get_window_pixels(Frontend *frontend, int *x, int *y);
+char *get_window_title(Frontend *frontend, int icon);
 /* Hint from backend to frontend about time-consuming operations.
  * Initial state is assumed to be BUSY_NOT. */
 enum {
@@ -748,8 +748,8 @@ enum {
 		       stuff is suspended */
     BUSY_CPU	    /* Locally busy (e.g. crypto); user interaction suspended */
 };
-void set_busy_status(void *frontend, int status);
-int frontend_is_utf8(void *frontend);
+void set_busy_status(Frontend *frontend, int status);
+int frontend_is_utf8(Frontend *frontend);
 
 void cleanup_exit(int);
 
@@ -1105,7 +1105,7 @@ FontSpec *platform_default_fontspec(const char *name);
  * Exports from terminal.c.
  */
 
-Terminal *term_init(Conf *, struct unicode_data *, void *);
+Terminal *term_init(Conf *, struct unicode_data *, Frontend *);
 void term_free(Terminal *);
 void term_size(Terminal *, int, int, int);
 void term_paint(Terminal *, Context, int, int, int, int, int);
@@ -1142,7 +1142,7 @@ int format_arrow_key(char *buf, Terminal *term, int xkey, int ctrl);
 /*
  * Exports from logging.c.
  */
-LogContext *log_init(void *frontend, Conf *conf);
+LogContext *log_init(Frontend *frontend, Conf *conf);
 void log_free(LogContext *logctx);
 void log_reconfig(LogContext *logctx, Conf *conf);
 void logfopen(LogContext *logctx);
@@ -1196,7 +1196,7 @@ extern const struct Backend_vtable ssh_backend;
 /*
  * Exports from ldisc.c.
  */
-Ldisc *ldisc_create(Conf *, Terminal *, Backend *, void *);
+Ldisc *ldisc_create(Conf *, Terminal *, Backend *, Frontend *);
 void ldisc_configure(Ldisc *, Conf *);
 void ldisc_free(Ldisc *);
 void ldisc_send(Ldisc *, const void *buf, int len, int interactive);
@@ -1324,7 +1324,7 @@ int wc_unescape(char *output, const char *wildcard);
 /*
  * Exports from frontend (windlg.c etc)
  */
-void logevent(void *frontend, const char *);
+void logevent(Frontend *frontend, const char *);
 void pgp_fingerprints(void);
 /*
  * verify_ssh_host_key() can return one of three values:
@@ -1338,7 +1338,7 @@ void pgp_fingerprints(void);
  *    back via the provided function with a result that's either 0
  *    or +1'.
  */
-int verify_ssh_host_key(void *frontend, char *host, int port,
+int verify_ssh_host_key(Frontend *frontend, char *host, int port,
                         const char *keytype, char *keystr, char *fingerprint,
                         void (*callback)(void *ctx, int result), void *ctx);
 /*
@@ -1354,9 +1354,9 @@ int have_ssh_host_key(const char *host, int port, const char *keytype);
  * warning threshold because that's all we have cached, but at least
  * one acceptable algorithm is available that we don't have cached.)
  */
-int askalg(void *frontend, const char *algtype, const char *algname,
+int askalg(Frontend *frontend, const char *algtype, const char *algname,
 	   void (*callback)(void *ctx, int result), void *ctx);
-int askhk(void *frontend, const char *algname, const char *betteralgs,
+int askhk(Frontend *frontend, const char *algname, const char *betteralgs,
           void (*callback)(void *ctx, int result), void *ctx);
 /*
  * askappend can return four values:
@@ -1366,7 +1366,7 @@ int askhk(void *frontend, const char *algname, const char *betteralgs,
  *  - 0 means cancel logging for this session
  *  - -1 means please wait.
  */
-int askappend(void *frontend, Filename *filename,
+int askappend(Frontend *frontend, Filename *filename,
 	      void (*callback)(void *ctx, int result), void *ctx);
 
 /*
@@ -1631,9 +1631,9 @@ struct IdempotentCallback {
 };
 void queue_idempotent_callback(struct IdempotentCallback *ic);
 
-typedef void (*toplevel_callback_notify_fn_t)(void *frontend);
+typedef void (*toplevel_callback_notify_fn_t)(void *ctx);
 void request_callback_notifications(toplevel_callback_notify_fn_t notify,
-                                    void *frontend);
+                                    void *ctx);
 
 /*
  * Define no-op macros for the jump list functions, on platforms that
diff --git a/raw.c b/raw.c
index 56eb0385..df280139 100644
--- a/raw.c
+++ b/raw.c
@@ -14,7 +14,7 @@ typedef struct raw_backend_data {
     Socket s;
     int closed_on_socket_error;
     int bufsize;
-    void *frontend;
+    Frontend *frontend;
     int sent_console_eof, sent_socket_eof, session_started;
 
     Conf *conf;
@@ -117,7 +117,7 @@ static const Plug_vtable Raw_plugvt = {
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static const char *raw_init(void *frontend_handle, Backend **backend_handle,
+static const char *raw_init(Frontend *frontend, Backend **backend_handle,
 			    Conf *conf,
 			    const char *host, int port, char **realhost,
                             int nodelay, int keepalive)
@@ -139,7 +139,7 @@ static const char *raw_init(void *frontend_handle, Backend **backend_handle,
     raw->session_started = FALSE;
     raw->conf = conf_copy(conf);
 
-    raw->frontend = frontend_handle;
+    raw->frontend = frontend;
 
     addressfamily = conf_get_int(conf, CONF_addressfamily);
     /*
diff --git a/rlogin.c b/rlogin.c
index 978e3084..05dd7dbb 100644
--- a/rlogin.c
+++ b/rlogin.c
@@ -18,7 +18,7 @@ typedef struct rlogin_tag {
     int firstbyte;
     int cansize;
     int term_width, term_height;
-    void *frontend;
+    Frontend *frontend;
 
     Conf *conf;
 
@@ -148,7 +148,7 @@ static const Plug_vtable Rlogin_plugvt = {
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static const char *rlogin_init(void *frontend_handle, Backend **backend_handle,
+static const char *rlogin_init(Frontend *frontend, Backend **backend_handle,
 			       Conf *conf,
 			       const char *host, int port, char **realhost,
 			       int nodelay, int keepalive)
@@ -165,7 +165,7 @@ static const char *rlogin_init(void *frontend_handle, Backend **backend_handle,
     rlogin->backend.vt = &rlogin_backend;
     rlogin->s = NULL;
     rlogin->closed_on_socket_error = FALSE;
-    rlogin->frontend = frontend_handle;
+    rlogin->frontend = frontend;
     rlogin->term_width = conf_get_int(conf, CONF_width);
     rlogin->term_height = conf_get_int(conf, CONF_height);
     rlogin->firstbyte = 1;
diff --git a/ssh.c b/ssh.c
index 952b901f..1009e038 100644
--- a/ssh.c
+++ b/ssh.c
@@ -729,7 +729,7 @@ struct ssh_tag {
     int echoing, editing;
 
     int session_started;
-    void *frontend;
+    Frontend *frontend;
 
     int ospeed, ispeed;		       /* temporaries */
     int term_width, term_height;
@@ -10665,7 +10665,7 @@ static void ssh_cache_conf_values(Ssh ssh)
  *
  * Returns an error message, or NULL on success.
  */
-static const char *ssh_init(void *frontend_handle, Backend **backend_handle,
+static const char *ssh_init(Frontend *frontend, Backend **backend_handle,
 			    Conf *conf,
                             const char *host, int port, char **realhost,
 			    int nodelay, int keepalive)
@@ -10781,7 +10781,7 @@ static const char *ssh_init(void *frontend_handle, Backend **backend_handle,
     ssh->backend.vt = &ssh_backend;
     *backend_handle = &ssh->backend;
 
-    ssh->frontend = frontend_handle;
+    ssh->frontend = frontend;
     ssh->term_width = conf_get_int(ssh->conf, CONF_width);
     ssh->term_height = conf_get_int(ssh->conf, CONF_height);
 
diff --git a/ssh.h b/ssh.h
index 4529bbcc..3fe8266b 100644
--- a/ssh.h
+++ b/ssh.h
@@ -660,7 +660,7 @@ int random_byte(void);
 void random_add_noise(void *noise, int length);
 void random_add_heavynoise(void *noise, int length);
 
-void logevent(void *, const char *);
+void logevent(Frontend *, const char *);
 
 struct PortForwarding;
 
diff --git a/telnet.c b/telnet.c
index 673c152f..7e62e301 100644
--- a/telnet.c
+++ b/telnet.c
@@ -172,7 +172,7 @@ typedef struct telnet_tag {
     Socket s;
     int closed_on_socket_error;
 
-    void *frontend;
+    Frontend *frontend;
     Ldisc *ldisc;
     int term_width, term_height;
 
@@ -705,7 +705,7 @@ static const Plug_vtable Telnet_plugvt = {
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static const char *telnet_init(void *frontend_handle, Backend **backend_handle,
+static const char *telnet_init(Frontend *frontend, Backend **backend_handle,
 			       Conf *conf, const char *host, int port,
 			       char **realhost, int nodelay, int keepalive)
 {
@@ -726,7 +726,7 @@ static const char *telnet_init(void *frontend_handle, Backend **backend_handle,
     telnet->activated = FALSE;
     telnet->sb_buf = NULL;
     telnet->sb_size = 0;
-    telnet->frontend = frontend_handle;
+    telnet->frontend = frontend;
     telnet->term_width = conf_get_int(telnet->conf, CONF_width);
     telnet->term_height = conf_get_int(telnet->conf, CONF_height);
     telnet->state = TOP_LEVEL;
diff --git a/terminal.c b/terminal.c
index 1dc83dc1..a8bd6fc7 100644
--- a/terminal.c
+++ b/terminal.c
@@ -1639,7 +1639,7 @@ const optionalrgb optionalrgb_none = {0, 0, 0, 0};
  * Initialise the terminal.
  */
 Terminal *term_init(Conf *myconf, struct unicode_data *ucsdata,
-		    void *frontend)
+                    Frontend *frontend)
 {
     Terminal *term;
 
diff --git a/terminal.h b/terminal.h
index 8ec256d4..f0727cf2 100644
--- a/terminal.h
+++ b/terminal.h
@@ -231,7 +231,7 @@ struct terminal_tag {
 
     Ldisc *ldisc;
 
-    void *frontend;
+    Frontend *frontend;
 
     LogContext *logctx;
 
diff --git a/testback.c b/testback.c
index f3e9e35f..01a7e6e0 100644
--- a/testback.c
+++ b/testback.c
@@ -32,9 +32,9 @@
 
 #include "putty.h"
 
-static const char *null_init(void *, Backend **, Conf *, const char *, int,
+static const char *null_init(Frontend *, Backend **, Conf *, const char *, int,
                              char **, int, int);
-static const char *loop_init(void *, Backend **, Conf *, const char *, int,
+static const char *loop_init(Frontend *, Backend **, Conf *, const char *, int,
                              char **, int, int);
 static void null_free(Backend *);
 static void loop_free(Backend *);
@@ -69,23 +69,23 @@ const struct Backend_vtable loop_backend = {
 };
 
 struct loop_state {
-    Terminal *term;
+    Frontend *frontend;
     Backend backend;
 };
 
-static const char *null_init(void *frontend_handle, Backend **backend_handle,
+static const char *null_init(Frontend *frontend, Backend **backend_handle,
                              Conf *conf, const char *host, int port,
 			     char **realhost, int nodelay, int keepalive) {
     *backend_handle = NULL;
     return NULL;
 }
 
-static const char *loop_init(void *frontend_handle, Backend **backend_handle,
+static const char *loop_init(Frontend *frontend, Backend **backend_handle,
                              Conf *conf, const char *host, int port,
 			     char **realhost, int nodelay, int keepalive) {
     struct loop_state *st = snew(struct loop_state);
 
-    st->term = frontend_handle;
+    st->frontend = frontend;
     *backend_handle = &st->backend;
     return NULL;
 }
@@ -114,7 +114,7 @@ static int null_send(Backend *be, const char *buf, int len) {
 static int loop_send(Backend *be, const char *buf, int len) {
     struct loop_state *st = FROMFIELD(be, struct loop_state, backend);
 
-    return from_backend(st->term, 0, buf, len);
+    return from_backend(st->frontend, 0, buf, len);
 }
 
 static int null_sendbuffer(Backend *be) {
diff --git a/unix/gtkapp.c b/unix/gtkapp.c
index d520565d..f79e5e9a 100644
--- a/unix/gtkapp.c
+++ b/unix/gtkapp.c
@@ -99,7 +99,7 @@ int main(int argc, char **argv)
     fprintf(stderr, "GtkApplication frontend doesn't work pre-GTK3\n");
     return 1;
 }
-GtkWidget *make_gtk_toplevel_window(void *frontend) { return NULL; }
+GtkWidget *make_gtk_toplevel_window(Frontend *frontend) { return NULL; }
 void launch_duplicate_session(Conf *conf) {}
 void launch_new_session(void) {}
 void launch_saved_session(const char *str) {}
@@ -204,7 +204,7 @@ WIN_ACTION_LIST(WIN_ACTION_ENTRY)
 };
 
 static GtkApplication *app;
-GtkWidget *make_gtk_toplevel_window(void *frontend)
+GtkWidget *make_gtk_toplevel_window(Frontend *frontend)
 {
     GtkWidget *win = gtk_application_window_new(app);
     g_action_map_add_action_entries(G_ACTION_MAP(win),
diff --git a/unix/gtkcomm.c b/unix/gtkcomm.c
index 9c3d1c53..6b6d19bb 100644
--- a/unix/gtkcomm.c
+++ b/unix/gtkcomm.c
@@ -221,7 +221,7 @@ static gint idle_toplevel_callback_func(gpointer data)
     return TRUE;
 }
 
-static void notify_toplevel_callback(void *frontend)
+static void notify_toplevel_callback(void *vctx)
 {
     if (!idle_fn_scheduled) {
         toplevel_callback_idle_id =
diff --git a/unix/gtkdlg.c b/unix/gtkdlg.c
index 737163f2..f1425daf 100644
--- a/unix/gtkdlg.c
+++ b/unix/gtkdlg.c
@@ -3442,7 +3442,7 @@ struct verify_ssh_host_key_result_ctx {
     char *keystr;
     void (*callback)(void *callback_ctx, int result);
     void *callback_ctx;
-    void *frontend;
+    Frontend *frontend;
 };
 
 static void verify_ssh_host_key_result_callback(void *vctx, int result)
@@ -3483,7 +3483,7 @@ static void verify_ssh_host_key_result_callback(void *vctx, int result)
     sfree(ctx);
 }
 
-int verify_ssh_host_key(void *frontend, char *host, int port,
+int verify_ssh_host_key(Frontend *frontend, char *host, int port,
                         const char *keytype, char *keystr, char *fingerprint,
                         void (*callback)(void *ctx, int result), void *ctx)
 {
@@ -3560,7 +3560,7 @@ int verify_ssh_host_key(void *frontend, char *host, int port,
 struct simple_prompt_result_ctx {
     void (*callback)(void *callback_ctx, int result);
     void *callback_ctx;
-    void *frontend;
+    Frontend *frontend;
     enum DialogSlot dialog_slot;
 };
 
@@ -3584,7 +3584,7 @@ static void simple_prompt_result_callback(void *vctx, int result)
  * Ask whether the selected algorithm is acceptable (since it was
  * below the configured 'warn' threshold).
  */
-int askalg(void *frontend, const char *algtype, const char *algname,
+int askalg(Frontend *frontend, const char *algtype, const char *algname,
 	   void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msg[] =
@@ -3616,7 +3616,7 @@ int askalg(void *frontend, const char *algtype, const char *algname,
     return -1;                         /* dialog still in progress */
 }
 
-int askhk(void *frontend, const char *algname, const char *betteralgs,
+int askhk(Frontend *frontend, const char *algname, const char *betteralgs,
           void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msg[] =
@@ -4059,7 +4059,7 @@ void logevent_dlg(void *estuff, const char *string)
     }
 }
 
-int askappend(void *frontend, Filename *filename,
+int askappend(Frontend *frontend, Filename *filename,
 	      void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msgtemplate[] =
diff --git a/unix/gtkmain.c b/unix/gtkmain.c
index 906d029a..a97f7415 100644
--- a/unix/gtkmain.c
+++ b/unix/gtkmain.c
@@ -549,7 +549,7 @@ int do_cmdline(int argc, char **argv, int do_everything, Conf *conf)
     return err;
 }
 
-GtkWidget *make_gtk_toplevel_window(void *frontend)
+GtkWidget *make_gtk_toplevel_window(Frontend *frontend)
 {
     return gtk_window_new(GTK_WINDOW_TOPLEVEL);
 }
diff --git a/unix/gtkwin.c b/unix/gtkwin.c
index 6867ac07..aebeff8f 100644
--- a/unix/gtkwin.c
+++ b/unix/gtkwin.c
@@ -76,7 +76,7 @@ struct clipboard_data_instance {
 #endif
 
 struct clipboard_state {
-    struct gui_data *inst;
+    Frontend *inst;
     int clipboard;
     GdkAtom atom;
 #ifdef JUST_USE_GTK_CLIPBOARD_UTF8
@@ -88,7 +88,7 @@ struct clipboard_state {
 #endif
 };
 
-struct gui_data {
+struct Frontend {
     GtkWidget *window, *area, *sbar;
     gboolean sbar_visible;
     gboolean drawing_area_got_size, drawing_area_realised;
@@ -182,7 +182,7 @@ struct gui_data {
 #endif
 };
 
-static void cache_conf_values(struct gui_data *inst)
+static void cache_conf_values(Frontend *inst)
 {
     inst->bold_style = conf_get_int(inst->conf, CONF_bold_style);
     inst->window_border = conf_get_int(inst->conf, CONF_window_border);
@@ -200,31 +200,31 @@ static void cache_conf_values(struct gui_data *inst)
 }
 
 struct draw_ctx {
-    struct gui_data *inst;
+    Frontend *inst;
     unifont_drawctx uctx;
 };
 
 static int send_raw_mouse;
 
-static void start_backend(struct gui_data *inst);
+static void start_backend(Frontend *inst);
 static void exit_callback(void *vinst);
-static void destroy_inst_connection(struct gui_data *inst);
-static void delete_inst(struct gui_data *inst);
+static void destroy_inst_connection(Frontend *inst);
+static void delete_inst(Frontend *inst);
 
 static void post_fatal_message_box_toplevel(void *vctx)
 {
-    struct gui_data *inst = (struct gui_data *)vctx;
+    Frontend *inst = (Frontend *)vctx;
     gtk_widget_destroy(inst->window);
 }
 
 static void post_fatal_message_box(void *vctx, int result)
 {
-    struct gui_data *inst = (struct gui_data *)vctx;
+    Frontend *inst = (Frontend *)vctx;
     unregister_dialog(inst, DIALOG_SLOT_CONNECTION_FATAL);
     queue_toplevel_callback(post_fatal_message_box_toplevel, inst);
 }
 
-void fatal_message_box(struct gui_data *inst, const char *msg)
+void fatal_message_box(Frontend *inst, const char *msg)
 {
     char *title = dupcat(appname, " Fatal Error", NULL);
     GtkWidget *dialog = create_message_box(
@@ -235,16 +235,14 @@ void fatal_message_box(struct gui_data *inst, const char *msg)
     sfree(title);
 }
 
-static void connection_fatal_callback(void *vinst)
+static void connection_fatal_callback(void *vctx)
 {
-    struct gui_data *inst = (struct gui_data *)vinst;
+    Frontend *inst = (Frontend *)vctx;
     destroy_inst_connection(inst);
 }
 
-void connection_fatal(void *frontend, const char *p, ...)
+void connection_fatal(Frontend *inst, const char *p, ...)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
-
     va_list ap;
     char *msg;
     va_start(ap, p);
@@ -254,7 +252,7 @@ void connection_fatal(void *frontend, const char *p, ...)
     sfree(msg);
 
     inst->exited = TRUE;   /* suppress normal exit handling */
-    queue_toplevel_callback(connection_fatal_callback, frontend);
+    queue_toplevel_callback(connection_fatal_callback, inst);
 }
 
 /*
@@ -293,36 +291,33 @@ int platform_default_i(const char *name, int def)
 }
 
 /* Dummy routine, only required in plink. */
-void frontend_echoedit_update(void *frontend, int echo, int edit)
+void frontend_echoedit_update(Frontend *inst, int echo, int edit)
 {
 }
 
-char *get_ttymode(void *frontend, const char *mode)
+char *get_ttymode(Frontend *inst, const char *mode)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     return term_get_ttymode(inst->term, mode);
 }
 
-int from_backend(void *frontend, int is_stderr, const void *data, int len)
+int from_backend(Frontend *inst, int is_stderr, const void *data, int len)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     return term_data(inst->term, is_stderr, data, len);
 }
 
-int from_backend_untrusted(void *frontend, const void *data, int len)
+int from_backend_untrusted(Frontend *inst, const void *data, int len)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     return term_data_untrusted(inst->term, data, len);
 }
 
-int from_backend_eof(void *frontend)
+int from_backend_eof(Frontend *inst)
 {
     return TRUE;   /* do respond to incoming EOF with outgoing */
 }
 
 int get_userpass_input(prompts_t *p, bufchain *input)
 {
-    struct gui_data *inst = (struct gui_data *)p->frontend;
+    Frontend *inst = p->frontend;
     int ret;
     ret = cmdline_get_passwd_input(p);
     if (ret == -1)
@@ -330,19 +325,15 @@ int get_userpass_input(prompts_t *p, bufchain *input)
     return ret;
 }
 
-void logevent(void *frontend, const char *string)
+void logevent(Frontend *inst, const char *string)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
-
     log_eventlog(inst->logctx, string);
 
     logevent_dlg(inst->eventlogstuff, string);
 }
 
-int font_dimension(void *frontend, int which)/* 0 for width, 1 for height */
+int font_dimension(Frontend *inst, int which) /* 0 for width, 1 for height */
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
-
     if (which)
 	return inst->font_height;
     else
@@ -360,8 +351,6 @@ int font_dimension(void *frontend, int which)/* 0 for width, 1 for height */
  */
 static Mouse_Button translate_button(Mouse_Button button)
 {
-    /* struct gui_data *inst = (struct gui_data *)frontend; */
-
     if (button == MBT_LEFT)
 	return MBT_SELECT;
     if (button == MBT_MIDDLE)
@@ -375,9 +364,8 @@ static Mouse_Button translate_button(Mouse_Button button)
  * Return the top-level GtkWindow associated with a particular
  * front end instance.
  */
-GtkWidget *get_window(void *frontend)
+GtkWidget *get_window(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     return inst->window;
 }
 
@@ -386,16 +374,14 @@ GtkWidget *get_window(void *frontend)
  * network code wanting to ask an asynchronous user question (e.g.
  * 'what about this dodgy host key, then?').
  */
-void register_dialog(void *frontend, enum DialogSlot slot, GtkWidget *dialog)
+void register_dialog(Frontend *inst, enum DialogSlot slot, GtkWidget *dialog)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     assert(slot < DIALOG_SLOT_LIMIT);
     assert(!inst->dialogs[slot]);
     inst->dialogs[slot] = dialog;
 }
-void unregister_dialog(void *frontend, enum DialogSlot slot)
+void unregister_dialog(Frontend *inst, enum DialogSlot slot)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     assert(slot < DIALOG_SLOT_LIMIT);
     assert(inst->dialogs[slot]);
     inst->dialogs[slot] = NULL;
@@ -405,13 +391,12 @@ void unregister_dialog(void *frontend, enum DialogSlot slot)
  * Minimise or restore the window in response to a server-side
  * request.
  */
-void set_iconic(void *frontend, int iconic)
+void set_iconic(Frontend *inst, int iconic)
 {
     /*
      * GTK 1.2 doesn't know how to do this.
      */
 #if GTK_CHECK_VERSION(2,0,0)
-    struct gui_data *inst = (struct gui_data *)frontend;
     if (iconic)
 	gtk_window_iconify(GTK_WINDOW(inst->window));
     else
@@ -422,9 +407,8 @@ void set_iconic(void *frontend, int iconic)
 /*
  * Move the window in response to a server-side request.
  */
-void move_window(void *frontend, int x, int y)
+void move_window(Frontend *inst, int x, int y)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     /*
      * I assume that when the GTK version of this call is available
      * we should use it. Not sure how it differs from the GDK one,
@@ -443,9 +427,8 @@ void move_window(void *frontend, int x, int y)
  * Move the window to the top or bottom of the z-order in response
  * to a server-side request.
  */
-void set_zorder(void *frontend, int top)
+void set_zorder(Frontend *inst, int top)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     if (top)
 	gdk_window_raise(gtk_widget_get_window(inst->window));
     else
@@ -455,9 +438,8 @@ void set_zorder(void *frontend, int top)
 /*
  * Refresh the window in response to a server-side request.
  */
-void refresh_window(void *frontend)
+void refresh_window(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     term_invalidate(inst->term);
 }
 
@@ -465,13 +447,12 @@ void refresh_window(void *frontend)
  * Maximise or restore the window in response to a server-side
  * request.
  */
-void set_zoomed(void *frontend, int zoomed)
+void set_zoomed(Frontend *inst, int zoomed)
 {
     /*
      * GTK 1.2 doesn't know how to do this.
      */
 #if GTK_CHECK_VERSION(2,0,0)
-    struct gui_data *inst = (struct gui_data *)frontend;
     if (zoomed)
 	gtk_window_maximize(GTK_WINDOW(inst->window));
     else
@@ -482,18 +463,16 @@ void set_zoomed(void *frontend, int zoomed)
 /*
  * Report whether the window is iconic, for terminal reports.
  */
-int is_iconic(void *frontend)
+int is_iconic(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     return !gdk_window_is_viewable(gtk_widget_get_window(inst->window));
 }
 
 /*
  * Report the window's position, for terminal reports.
  */
-void get_window_pos(void *frontend, int *x, int *y)
+void get_window_pos(Frontend *inst, int *x, int *y)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     /*
      * I assume that when the GTK version of this call is available
      * we should use it. Not sure how it differs from the GDK one,
@@ -509,9 +488,8 @@ void get_window_pos(void *frontend, int *x, int *y)
 /*
  * Report the window's pixel size, for terminal reports.
  */
-void get_window_pixels(void *frontend, int *x, int *y)
+void get_window_pixels(Frontend *inst, int *x, int *y)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     /*
      * I assume that when the GTK version of this call is available
      * we should use it. Not sure how it differs from the GDK one,
@@ -530,7 +508,7 @@ void get_window_pixels(void *frontend, int *x, int *y)
  * raise it, so that the user realises they've already been asked this
  * question.
  */
-static int find_and_raise_dialog(struct gui_data *inst, enum DialogSlot slot)
+static int find_and_raise_dialog(Frontend *inst, enum DialogSlot slot)
 {
     GtkWidget *dialog = inst->dialogs[slot];
     if (!dialog)
@@ -546,15 +524,14 @@ static int find_and_raise_dialog(struct gui_data *inst, enum DialogSlot slot)
 /*
  * Return the window or icon title.
  */
-char *get_window_title(void *frontend, int icon)
+char *get_window_title(Frontend *inst, int icon)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     return icon ? inst->icontitle : inst->wintitle;
 }
 
 static void warn_on_close_callback(void *vctx, int result)
 {
-    struct gui_data *inst = (struct gui_data *)vctx;
+    Frontend *inst = (Frontend *)vctx;
     unregister_dialog(inst, DIALOG_SLOT_WARN_ON_CLOSE);
     if (result)
         gtk_widget_destroy(inst->window);
@@ -570,9 +547,8 @@ static void warn_on_close_callback(void *vctx, int result)
  * handler need not do anything', i.e. 'suppress default handler',
  * i.e. 'do not close the window'.)
  */
-gint delete_window(GtkWidget *widget, GdkEvent *event, gpointer data)
+gint delete_window(GtkWidget *widget, GdkEvent *event, Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)data;
     if (!inst->exited && conf_get_int(inst->conf, CONF_warn_on_close)) {
         /*
          * We're not going to exit right now. We must put up a
@@ -594,7 +570,7 @@ gint delete_window(GtkWidget *widget, GdkEvent *event, gpointer data)
     return FALSE;
 }
 
-static void update_mouseptr(struct gui_data *inst)
+static void update_mouseptr(Frontend *inst)
 {
     switch (inst->busy_status) {
       case BUSY_NOT:
@@ -620,7 +596,7 @@ static void update_mouseptr(struct gui_data *inst)
     }
 }
 
-static void show_mouseptr(struct gui_data *inst, int show)
+static void show_mouseptr(Frontend *inst, int show)
 {
     if (!conf_get_int(inst->conf, CONF_hide_mouseptr))
 	show = 1;
@@ -628,9 +604,9 @@ static void show_mouseptr(struct gui_data *inst, int show)
     update_mouseptr(inst);
 }
 
-static void draw_backing_rect(struct gui_data *inst);
+static void draw_backing_rect(Frontend *inst);
 
-static void drawing_area_setup(struct gui_data *inst, int width, int height)
+static void drawing_area_setup(Frontend *inst, int width, int height)
 {
     int w, h, new_scale, need_size = 0;
 
@@ -719,7 +695,7 @@ static void drawing_area_setup(struct gui_data *inst, int width, int height)
 #endif
 }
 
-static void drawing_area_setup_simple(struct gui_data *inst)
+static void drawing_area_setup_simple(Frontend *inst)
 {
     /*
      * Wrapper on drawing_area_setup which fetches the width and
@@ -736,10 +712,8 @@ static void drawing_area_setup_simple(struct gui_data *inst)
     drawing_area_setup(inst, alloc.width, alloc.height);
 }
 
-static void area_realised(GtkWidget *widget, gpointer data)
+static void area_realised(GtkWidget *widget, Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)data;
-
     inst->drawing_area_realised = TRUE;
     if (inst->drawing_area_realised && inst->drawing_area_got_size &&
         inst->drawing_area_setup_needed)
@@ -747,17 +721,15 @@ static void area_realised(GtkWidget *widget, gpointer data)
 }
 
 static void area_size_allocate(
-    GtkWidget *widget, GdkRectangle *alloc, gpointer data)
+    GtkWidget *widget, GdkRectangle *alloc, Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)data;
-
     inst->drawing_area_got_size = TRUE;
     if (inst->drawing_area_realised && inst->drawing_area_got_size)
         drawing_area_setup(inst, alloc->width, alloc->height);
 }
 
 #if GTK_CHECK_VERSION(3,10,0)
-static void area_check_scale(struct gui_data *inst)
+static void area_check_scale(Frontend *inst)
 {
     if (!inst->drawing_area_setup_needed &&
         inst->scale != gtk_widget_get_scale_factor(inst->area)) {
@@ -774,7 +746,7 @@ static void area_check_scale(struct gui_data *inst)
 static gboolean area_configured(
     GtkWidget *widget, GdkEventConfigure *event, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     area_check_scale(inst);
     return FALSE;
 }
@@ -799,7 +771,7 @@ static void cairo_setup_dctx(struct draw_ctx *dctx)
 #if GTK_CHECK_VERSION(3,0,0)
 static gint draw_area(GtkWidget *widget, cairo_t *cr, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
 
 #if GTK_CHECK_VERSION(3,10,0)
     /*
@@ -862,7 +834,7 @@ static gint draw_area(GtkWidget *widget, cairo_t *cr, gpointer data)
 #else
 gint expose_area(GtkWidget *widget, GdkEventExpose *event, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
 
 #ifndef NO_BACKING_PIXMAPS
     /*
@@ -912,11 +884,11 @@ char *dup_keyval_name(guint keyval)
 }
 #endif
 
-static void change_font_size(struct gui_data *inst, int increment);
+static void change_font_size(Frontend *inst, int increment);
 
 gint key_event(GtkWidget *widget, GdkEventKey *event, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     char output[256];
     wchar_t ucsoutput[2];
     int ucsval, start, end, special, output_charset, use_ucsoutput;
@@ -2146,7 +2118,7 @@ gint key_event(GtkWidget *widget, GdkEventKey *event, gpointer data)
 #if GTK_CHECK_VERSION(2,0,0)
 void input_method_commit_event(GtkIMContext *imc, gchar *str, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
 
 #ifdef KEY_EVENT_DIAGNOSTICS
     char *string_string = dupstr("");
@@ -2173,7 +2145,7 @@ void input_method_commit_event(GtkIMContext *imc, gchar *str, gpointer data)
 #define SCROLL_INCREMENT_LINES 5
 
 #if GTK_CHECK_VERSION(3,4,0)
-gboolean scroll_internal(struct gui_data *inst, gdouble delta, guint state,
+gboolean scroll_internal(Frontend *inst, gdouble delta, guint state,
 			 gdouble ex, gdouble ey)
 {
     int shift, ctrl, alt, x, y, raw_mouse_mode;
@@ -2225,7 +2197,7 @@ gboolean scroll_internal(struct gui_data *inst, gdouble delta, guint state,
 }
 #endif
 
-static gboolean button_internal(struct gui_data *inst, GdkEventButton *event)
+static gboolean button_internal(Frontend *inst, GdkEventButton *event)
 {
     int shift, ctrl, alt, x, y, button, act, raw_mouse_mode;
 
@@ -2298,7 +2270,7 @@ static gboolean button_internal(struct gui_data *inst, GdkEventButton *event)
 
 gboolean button_event(GtkWidget *widget, GdkEventButton *event, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     return button_internal(inst, event);
 }
 
@@ -2310,7 +2282,7 @@ gboolean button_event(GtkWidget *widget, GdkEventButton *event, gpointer data)
  */
 gboolean scroll_event(GtkWidget *widget, GdkEventScroll *event, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
 
 #if GTK_CHECK_VERSION(3,4,0)
     gdouble dx, dy;
@@ -2351,7 +2323,7 @@ gboolean scroll_event(GtkWidget *widget, GdkEventScroll *event, gpointer data)
 
 gint motion_event(GtkWidget *widget, GdkEventMotion *event, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     int shift, ctrl, alt, x, y, button;
 
     /* Remember the timestamp. */
@@ -2380,10 +2352,8 @@ gint motion_event(GtkWidget *widget, GdkEventMotion *event, gpointer data)
     return TRUE;
 }
 
-void frontend_keypress(void *handle)
+void frontend_keypress(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)handle;
-
     /*
      * If our child process has exited but not closed, terminate on
      * any keypress.
@@ -2392,9 +2362,9 @@ void frontend_keypress(void *handle)
         gtk_widget_destroy(inst->window);
 }
 
-static void exit_callback(void *vinst)
+static void exit_callback(void *vctx)
 {
-    struct gui_data *inst = (struct gui_data *)vinst;
+    Frontend *inst = (Frontend *)vctx;
     int exitcode, close_on_exit;
 
     if (!inst->exited &&
@@ -2409,14 +2379,12 @@ static void exit_callback(void *vinst)
     }
 }
 
-void notify_remote_exit(void *frontend)
+void notify_remote_exit(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
-
     queue_toplevel_callback(exit_callback, inst);
 }
 
-static void destroy_inst_connection(struct gui_data *inst)
+static void destroy_inst_connection(Frontend *inst)
 {
     inst->exited = TRUE;
     if (inst->ldisc) {
@@ -2435,7 +2403,7 @@ static void destroy_inst_connection(struct gui_data *inst)
     }
 }
 
-static void delete_inst(struct gui_data *inst)
+static void delete_inst(Frontend *inst)
 {
     int dialog_slot;
     for (dialog_slot = 0; dialog_slot < DIALOG_SLOT_LIMIT; dialog_slot++) {
@@ -2496,7 +2464,7 @@ static void delete_inst(struct gui_data *inst)
 
 void destroy(GtkWidget *widget, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     inst->window = NULL;
     delete_inst(inst);
     session_window_closed();
@@ -2504,16 +2472,15 @@ void destroy(GtkWidget *widget, gpointer data)
 
 gint focus_event(GtkWidget *widget, GdkEventFocus *event, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     term_set_focus(inst->term, event->in);
     term_update(inst->term);
     show_mouseptr(inst, 1);
     return FALSE;
 }
 
-void set_busy_status(void *frontend, int status)
+void set_busy_status(Frontend *inst, int status)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     inst->busy_status = status;
     update_mouseptr(inst);
 }
@@ -2521,24 +2488,21 @@ void set_busy_status(void *frontend, int status)
 /*
  * set or clear the "raw mouse message" mode
  */
-void set_raw_mouse_mode(void *frontend, int activate)
+void set_raw_mouse_mode(Frontend *inst, int activate)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     activate = activate && !conf_get_int(inst->conf, CONF_no_mouse_rep);
     send_raw_mouse = activate;
     update_mouseptr(inst);
 }
 
 #if GTK_CHECK_VERSION(2,0,0)
-static void compute_whole_window_size(struct gui_data *inst,
+static void compute_whole_window_size(Frontend *inst,
                                       int wchars, int hchars,
                                       int *wpix, int *hpix);
 #endif
 
-void request_resize(void *frontend, int w, int h)
+void request_resize(Frontend *inst, int w, int h)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
-
 #if !GTK_CHECK_VERSION(3,0,0)
 
     int large_x, large_y;
@@ -2624,7 +2588,7 @@ void request_resize(void *frontend, int w, int h)
 
 }
 
-static void real_palette_set(struct gui_data *inst, int n, int r, int g, int b)
+static void real_palette_set(Frontend *inst, int n, int r, int g, int b)
 {
     inst->cols[n].red = r * 0x0101;
     inst->cols[n].green = g * 0x0101;
@@ -2678,7 +2642,7 @@ void set_gtk_widget_background(GtkWidget *widget, const GdkColor *col)
 #endif
 }
 
-void set_window_background(struct gui_data *inst)
+void set_window_background(Frontend *inst)
 {
     if (inst->area)
 	set_gtk_widget_background(GTK_WIDGET(inst->area), &inst->cols[258]);
@@ -2686,9 +2650,8 @@ void set_window_background(struct gui_data *inst)
 	set_gtk_widget_background(GTK_WIDGET(inst->window), &inst->cols[258]);
 }
 
-void palette_set(void *frontend, int n, int r, int g, int b)
+void palette_set(Frontend *inst, int n, int r, int g, int b)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     if (n >= 16)
 	n += 256 - 16;
     if (n >= NALLCOLOURS)
@@ -2703,9 +2666,8 @@ void palette_set(void *frontend, int n, int r, int g, int b)
     }
 }
 
-int palette_get(void *frontend, int n, int *r, int *g, int *b)
+int palette_get(Frontend *inst, int n, int *r, int *g, int *b)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     if (n < 0 || n >= NALLCOLOURS)
 	return FALSE;
     *r = inst->cols[n].red >> 8;
@@ -2714,9 +2676,8 @@ int palette_get(void *frontend, int n, int *r, int *g, int *b)
     return TRUE;
 }
 
-void palette_reset(void *frontend)
+void palette_reset(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     /* This maps colour indices in inst->conf to those used in inst->cols. */
     static const int ww[] = {
 	256, 257, 258, 259, 260, 261,
@@ -2784,7 +2745,7 @@ void palette_reset(void *frontend)
 }
 
 static struct clipboard_state *clipboard_from_atom(
-    struct gui_data *inst, GdkAtom atom)
+    Frontend *inst, GdkAtom atom)
 {
     int i;
 
@@ -2806,7 +2767,7 @@ static struct clipboard_state *clipboard_from_atom(
  * formats it feels like.
  */
 
-void set_clipboard_atom(struct gui_data *inst, int clipboard, GdkAtom atom)
+void set_clipboard_atom(Frontend *inst, int clipboard, GdkAtom atom)
 {
     struct clipboard_state *state = &inst->clipstates[clipboard];
 
@@ -2823,7 +2784,7 @@ void set_clipboard_atom(struct gui_data *inst, int clipboard, GdkAtom atom)
     }
 }
 
-int init_clipboard(struct gui_data *inst)
+int init_clipboard(Frontend *inst)
 {
     set_clipboard_atom(inst, CLIP_PRIMARY, GDK_SELECTION_PRIMARY);
     set_clipboard_atom(inst, CLIP_CLIPBOARD, clipboard_atom);
@@ -2861,11 +2822,10 @@ static void clipboard_clear(GtkClipboard *clipboard, gpointer data)
     sfree(cdi);
 }
 
-void write_clip(void *frontend, int clipboard,
+void write_clip(Frontend *inst, int clipboard,
                 wchar_t *data, int *attr, truecolour *truecolour, int len,
                 int must_deselect)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     struct clipboard_state *state = &inst->clipstates[clipboard];
     struct clipboard_data_instance *cdi;
 
@@ -2922,7 +2882,7 @@ void write_clip(void *frontend, int clipboard,
 static void clipboard_text_received(GtkClipboard *clipboard,
                                     const gchar *text, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     wchar_t *paste;
     int paste_len;
     int length;
@@ -2940,9 +2900,8 @@ static void clipboard_text_received(GtkClipboard *clipboard,
     sfree(paste);
 }
 
-void frontend_request_paste(void *frontend, int clipboard)
+void frontend_request_paste(Frontend *inst, int clipboard)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     struct clipboard_state *state = &inst->clipstates[clipboard];
 
     if (!state->gtkclipboard)
@@ -2975,7 +2934,7 @@ void frontend_request_paste(void *frontend, int clipboard)
  */
 
 /* Store the data in a cut-buffer. */
-static void store_cutbuffer(struct gui_data *inst, char *ptr, int len)
+static void store_cutbuffer(Frontend *inst, char *ptr, int len)
 {
 #ifndef NOT_X_WINDOWS
     if (inst->disp) {
@@ -2989,7 +2948,7 @@ static void store_cutbuffer(struct gui_data *inst, char *ptr, int len)
 /* Retrieve data from a cut-buffer.
  * Returned data needs to be freed with XFree().
  */
-static char *retrieve_cutbuffer(struct gui_data *inst, int *nbytes)
+static char *retrieve_cutbuffer(Frontend *inst, int *nbytes)
 {
 #ifndef NOT_X_WINDOWS
     char *ptr;
@@ -3009,11 +2968,10 @@ static char *retrieve_cutbuffer(struct gui_data *inst, int *nbytes)
 #endif
 }
 
-void write_clip(void *frontend, int clipboard,
+void write_clip(Frontend *inst, int clipboard,
                 wchar_t *data, int *attr, truecolour *truecolour, int len,
                 int must_deselect)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     struct clipboard_state *state = &inst->clipstates[clipboard];
 
     if (state->pasteout_data)
@@ -3115,7 +3073,7 @@ void write_clip(void *frontend, int clipboard,
 static void selection_get(GtkWidget *widget, GtkSelectionData *seldata,
                           guint info, guint time_stamp, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     GdkAtom target = gtk_selection_data_get_target(seldata);
     struct clipboard_state *state = clipboard_from_atom(
         inst, gtk_selection_data_get_selection(seldata));
@@ -3140,7 +3098,7 @@ static void selection_get(GtkWidget *widget, GtkSelectionData *seldata,
 static gint selection_clear(GtkWidget *widget, GdkEventSelection *seldata,
                             gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     struct clipboard_state *state = clipboard_from_atom(
         inst, seldata->selection);
 
@@ -3163,9 +3121,8 @@ static gint selection_clear(GtkWidget *widget, GdkEventSelection *seldata,
     return TRUE;
 }
 
-void frontend_request_paste(void *frontend, int clipboard)
+void frontend_request_paste(Frontend *inst, int clipboard)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     struct clipboard_state *state = &inst->clipstates[clipboard];
 
     /*
@@ -3198,7 +3155,7 @@ void frontend_request_paste(void *frontend, int clipboard)
 static void selection_received(GtkWidget *widget, GtkSelectionData *seldata,
                                guint time, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     char *text;
     int length;
 #ifndef NOT_X_WINDOWS
@@ -3320,7 +3277,7 @@ static void selection_received(GtkWidget *widget, GtkSelectionData *seldata,
 #endif
 }
 
-static void init_one_clipboard(struct gui_data *inst, int clipboard)
+static void init_one_clipboard(Frontend *inst, int clipboard)
 {
     struct clipboard_state *state = &inst->clipstates[clipboard];
 
@@ -3328,7 +3285,7 @@ static void init_one_clipboard(struct gui_data *inst, int clipboard)
     state->clipboard = clipboard;
 }
 
-void set_clipboard_atom(struct gui_data *inst, int clipboard, GdkAtom atom)
+void set_clipboard_atom(Frontend *inst, int clipboard, GdkAtom atom)
 {
     struct clipboard_state *state = &inst->clipstates[clipboard];
 
@@ -3338,7 +3295,7 @@ void set_clipboard_atom(struct gui_data *inst, int clipboard, GdkAtom atom)
     state->atom = atom;
 }
 
-void init_clipboard(struct gui_data *inst)
+void init_clipboard(Frontend *inst)
 {
 #ifndef NOT_X_WINDOWS
     /*
@@ -3394,7 +3351,7 @@ void init_clipboard(struct gui_data *inst)
 
 #endif /* JUST_USE_GTK_CLIPBOARD_UTF8 */
 
-static void set_window_titles(struct gui_data *inst)
+static void set_window_titles(Frontend *inst)
 {
     /*
      * We must always call set_icon_name after calling set_title,
@@ -3407,25 +3364,22 @@ static void set_window_titles(struct gui_data *inst)
                                  inst->icontitle);
 }
 
-void set_title(void *frontend, char *title)
+void set_title(Frontend *inst, char *title)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     sfree(inst->wintitle);
     inst->wintitle = dupstr(title);
     set_window_titles(inst);
 }
 
-void set_icon(void *frontend, char *title)
+void set_icon(Frontend *inst, char *title)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     sfree(inst->icontitle);
     inst->icontitle = dupstr(title);
     set_window_titles(inst);
 }
 
-void set_title_and_icon(void *frontend, char *title, char *icon)
+void set_title_and_icon(Frontend *inst, char *title, char *icon)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     sfree(inst->wintitle);
     inst->wintitle = dupstr(title);
     sfree(inst->icontitle);
@@ -3433,9 +3387,8 @@ void set_title_and_icon(void *frontend, char *title, char *icon)
     set_window_titles(inst);
 }
 
-void set_sbar(void *frontend, int total, int start, int page)
+void set_sbar(Frontend *inst, int total, int start, int page)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     if (!conf_get_int(inst->conf, CONF_scrollbar))
 	return;
     inst->ignore_sbar = TRUE;
@@ -3451,17 +3404,15 @@ void set_sbar(void *frontend, int total, int start, int page)
     inst->ignore_sbar = FALSE;
 }
 
-void scrollbar_moved(GtkAdjustment *adj, gpointer data)
+void scrollbar_moved(GtkAdjustment *adj, Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)data;
-
     if (!conf_get_int(inst->conf, CONF_scrollbar))
 	return;
     if (!inst->ignore_sbar)
 	term_scroll(inst->term, 1, (int)gtk_adjustment_get_value(adj));
 }
 
-static void show_scrollbar(struct gui_data *inst, gboolean visible)
+static void show_scrollbar(Frontend *inst, gboolean visible)
 {
     inst->sbar_visible = visible;
     if (visible)
@@ -3470,7 +3421,7 @@ static void show_scrollbar(struct gui_data *inst, gboolean visible)
         gtk_widget_hide(inst->sbar);
 }
 
-void sys_cursor(void *frontend, int x, int y)
+void sys_cursor(Frontend *frontend, int x, int y)
 {
     /*
      * This is meaningless under X.
@@ -3483,7 +3434,7 @@ void sys_cursor(void *frontend, int x, int y)
  * may want to perform additional actions on any kind of bell (for
  * example, taskbar flashing in Windows).
  */
-void do_beep(void *frontend, int mode)
+void do_beep(Frontend *frontend, int mode)
 {
     if (mode == BELL_DEFAULT)
         gdk_display_beep(gdk_display_get_default());
@@ -3498,9 +3449,8 @@ int char_width(Context ctx, int uc)
     return 1;
 }
 
-Context get_ctx(void *frontend)
+Context get_ctx(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     struct draw_ctx *dctx;
 
     if (!gtk_widget_get_window(inst->area))
@@ -3534,7 +3484,7 @@ Context get_ctx(void *frontend)
 void free_ctx(Context ctx)
 {
     struct draw_ctx *dctx = (struct draw_ctx *)ctx;
-    /* struct gui_data *inst = dctx->inst; */
+    /* Frontend *inst = dctx->inst; */
 #ifdef DRAW_TEXT_GDK
     if (dctx->uctx.type == DRAWTYPE_GDK) {
         gdk_gc_unref(dctx->uctx.u.gdk.gc);
@@ -3824,7 +3774,7 @@ static void draw_stretch_after(struct draw_ctx *dctx, int x, int y,
 #endif
 }
 
-static void draw_backing_rect(struct gui_data *inst)
+static void draw_backing_rect(Frontend *inst)
 {
     int w, h;
     struct draw_ctx *dctx = get_ctx(inst);
@@ -3850,7 +3800,7 @@ void do_text_internal(Context ctx, int x, int y, wchar_t *text, int len,
 		      unsigned long attr, int lattr, truecolour truecolour)
 {
     struct draw_ctx *dctx = (struct draw_ctx *)ctx;
-    struct gui_data *inst = dctx->inst;
+    Frontend *inst = dctx->inst;
     int ncombining;
     int nfg, nbg, t, fontid, shadow, rlen, widefactor, bold;
     int monochrome =
@@ -4007,7 +3957,7 @@ void do_text(Context ctx, int x, int y, wchar_t *text, int len,
 	     unsigned long attr, int lattr, truecolour truecolour)
 {
     struct draw_ctx *dctx = (struct draw_ctx *)ctx;
-    struct gui_data *inst = dctx->inst;
+    Frontend *inst = dctx->inst;
     int widefactor;
 
     do_text_internal(ctx, x, y, text, len, attr, lattr, truecolour);
@@ -4037,7 +3987,7 @@ void do_cursor(Context ctx, int x, int y, wchar_t *text, int len,
 	       unsigned long attr, int lattr, truecolour truecolour)
 {
     struct draw_ctx *dctx = (struct draw_ctx *)ctx;
-    struct gui_data *inst = dctx->inst;
+    Frontend *inst = dctx->inst;
 
     int active, passive, widefactor;
 
@@ -4149,7 +4099,7 @@ void do_cursor(Context ctx, int x, int y, wchar_t *text, int len,
 #endif
 }
 
-GdkCursor *make_mouse_ptr(struct gui_data *inst, int cursor_val)
+GdkCursor *make_mouse_ptr(Frontend *inst, int cursor_val)
 {
     if (cursor_val == -1) {
 #if GTK_CHECK_VERSION(2,16,0)
@@ -4186,15 +4136,14 @@ void modalfatalbox(const char *p, ...)
     exit(1);
 }
 
-const char *get_x_display(void *frontend)
+const char *get_x_display(Frontend *frontend)
 {
     return gdk_get_display();
 }
 
 #ifndef NOT_X_WINDOWS
-int get_windowid(void *frontend, long *id)
+int get_windowid(Frontend *inst, long *id)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     GdkWindow *window = gtk_widget_get_window(inst->area);
     if (!GDK_IS_X11_WINDOW(window))
         return FALSE;
@@ -4203,13 +4152,12 @@ int get_windowid(void *frontend, long *id)
 }
 #endif
 
-int frontend_is_utf8(void *frontend)
+int frontend_is_utf8(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
     return inst->ucsdata.line_codepage == CS_UTF8;
 }
 
-char *setup_fonts_ucs(struct gui_data *inst)
+char *setup_fonts_ucs(Frontend *inst)
 {
     int shadowbold = conf_get_int(inst->conf, CONF_shadowbold);
     int shadowboldoffset = conf_get_int(inst->conf, CONF_shadowboldoffset);
@@ -4312,7 +4260,7 @@ static void find_app_menu_bar(GtkWidget *widget, gpointer data)
 }
 #endif
 
-static void compute_geom_hints(struct gui_data *inst, GdkGeometry *geom)
+static void compute_geom_hints(Frontend *inst, GdkGeometry *geom)
 {
     /*
      * Unused fields in geom.
@@ -4413,7 +4361,7 @@ static void compute_geom_hints(struct gui_data *inst, GdkGeometry *geom)
 #endif
 }
 
-void set_geom_hints(struct gui_data *inst)
+void set_geom_hints(Frontend *inst)
 {
     GdkGeometry geom;
     gint flags = GDK_HINT_MIN_SIZE | GDK_HINT_BASE_SIZE | GDK_HINT_RESIZE_INC;
@@ -4427,7 +4375,7 @@ void set_geom_hints(struct gui_data *inst)
 }
 
 #if GTK_CHECK_VERSION(2,0,0)
-static void compute_whole_window_size(struct gui_data *inst,
+static void compute_whole_window_size(Frontend *inst,
                                       int wchars, int hchars,
                                       int *wpix, int *hpix)
 {
@@ -4440,13 +4388,13 @@ static void compute_whole_window_size(struct gui_data *inst,
 
 void clear_scrollback_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     term_clrsb(inst->term);
 }
 
 void reset_terminal_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     term_pwron(inst->term, TRUE);
     if (inst->ldisc)
 	ldisc_echoedit_update(inst->ldisc);
@@ -4454,27 +4402,27 @@ void reset_terminal_menuitem(GtkMenuItem *item, gpointer data)
 
 void copy_clipboard_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     static const int clips[] = { MENU_CLIPBOARD };
     term_request_copy(inst->term, clips, lenof(clips));
 }
 
 void paste_clipboard_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     term_request_paste(inst->term, MENU_CLIPBOARD);
 }
 
 void copy_all_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     static const int clips[] = { COPYALL_CLIPBOARDS };
     term_copyall(inst->term, clips, lenof(clips));
 }
 
 void special_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     int code = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(item),
                                                  "user-data"));
 
@@ -4484,17 +4432,17 @@ void special_menuitem(GtkMenuItem *item, gpointer data)
 
 void about_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     about_box(inst->window);
 }
 
 void event_log_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     showeventlog(inst->eventlogstuff, inst->window);
 }
 
-void setup_clipboards(struct gui_data *inst, Terminal *term, Conf *conf)
+void setup_clipboards(Frontend *inst, Terminal *term, Conf *conf)
 {
     assert(term->mouse_select_clipboards[0] == CLIP_LOCAL);
 
@@ -4556,7 +4504,7 @@ void setup_clipboards(struct gui_data *inst, Terminal *term, Conf *conf)
 }
 
 struct after_change_settings_dialog_ctx {
-    struct gui_data *inst;
+    Frontend *inst;
     Conf *newconf;
 };
 
@@ -4564,7 +4512,7 @@ static void after_change_settings_dialog(void *vctx, int retval);
 
 void change_settings_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     struct after_change_settings_dialog_ctx *ctx;
     GtkWidget *dialog;
     char *title;
@@ -4597,7 +4545,7 @@ static void after_change_settings_dialog(void *vctx, int retval)
     };
     struct after_change_settings_dialog_ctx ctx =
         *(struct after_change_settings_dialog_ctx *)vctx;
-    struct gui_data *inst = ctx.inst;
+    Frontend *inst = ctx.inst;
     Conf *oldconf = inst->conf, *newconf = ctx.newconf;
     int i, j, need_size;
 
@@ -4772,7 +4720,7 @@ static void after_change_settings_dialog(void *vctx, int retval)
     }
 }
 
-static void change_font_size(struct gui_data *inst, int increment)
+static void change_font_size(Frontend *inst, int increment)
 {
     static const int conf_keys[lenof(inst->fonts)] = {
         CONF_font, CONF_boldfont, CONF_widefont, CONF_wideboldfont,
@@ -4835,7 +4783,7 @@ static void change_font_size(struct gui_data *inst, int increment)
 
 void dup_session_menuitem(GtkMenuItem *item, gpointer gdata)
 {
-    struct gui_data *inst = (struct gui_data *)gdata;
+    Frontend *inst = (Frontend *)gdata;
 
     launch_duplicate_session(inst->conf);
 }
@@ -4847,7 +4795,7 @@ void new_session_menuitem(GtkMenuItem *item, gpointer data)
 
 void restart_session_menuitem(GtkMenuItem *item, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
 
     if (!inst->backend) {
 	logevent(inst, "----- Session restarted -----");
@@ -4871,9 +4819,9 @@ void saved_session_freedata(GtkMenuItem *item, gpointer data)
     sfree(str);
 }
 
-void app_menu_action(void *frontend, enum MenuAction action)
+void app_menu_action(Frontend *frontend, enum MenuAction action)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
+    Frontend *inst = (Frontend *)frontend;
     switch (action) {
       case MA_COPY:
         copy_clipboard_menuitem(NULL, inst);
@@ -4907,7 +4855,7 @@ void app_menu_action(void *frontend, enum MenuAction action)
 
 static void update_savedsess_menu(GtkMenuItem *menuitem, gpointer data)
 {
-    struct gui_data *inst = (struct gui_data *)data;
+    Frontend *inst = (Frontend *)data;
     struct sesslist sesslist;
     int i;
 
@@ -4976,10 +4924,8 @@ void set_window_icon(GtkWidget *window, const char *const *const *icon,
 #endif
 }
 
-void update_specials_menu(void *frontend)
+void update_specials_menu(Frontend *inst)
 {
-    struct gui_data *inst = (struct gui_data *)frontend;
-
     const struct telnet_special *specials;
 
     if (inst->backend)
@@ -5041,7 +4987,7 @@ void update_specials_menu(void *frontend)
     }
 }
 
-static void start_backend(struct gui_data *inst)
+static void start_backend(Frontend *inst)
 {
     const struct Backend_vtable *vt;
     char *realhost;
@@ -5114,14 +5060,14 @@ static void get_monitor_geometry(GtkWidget *widget, GdkRectangle *geometry)
 
 void new_session_window(Conf *conf, const char *geometry_string)
 {
-    struct gui_data *inst;
+    Frontend *inst;
 
     prepare_session(conf);
 
     /*
      * Create an instance structure and initialise to zeroes
      */
-    inst = snew(struct gui_data);
+    inst = snew(Frontend);
     memset(inst, 0, sizeof(*inst));
 #ifdef JUST_USE_GTK_CLIPBOARD_UTF8
     inst->cdi_headtail.next = inst->cdi_headtail.prev = &inst->cdi_headtail;
diff --git a/unix/unix.h b/unix/unix.h
index f9ff3c68..3dd2864a 100644
--- a/unix/unix.h
+++ b/unix/unix.h
@@ -175,7 +175,7 @@ void launch_saved_session(const char *str);
 void session_window_closed(void);
 void window_setup_error(const char *errmsg);
 #ifdef MAY_REFER_TO_GTK_IN_HEADERS
-GtkWidget *make_gtk_toplevel_window(void *frontend);
+GtkWidget *make_gtk_toplevel_window(Frontend *frontend);
 #endif
 
 const struct Backend_vtable *select_backend(Conf *conf);
@@ -189,16 +189,16 @@ enum MenuAction {
     MA_RESTART_SESSION, MA_CHANGE_SETTINGS, MA_CLEAR_SCROLLBACK,
     MA_RESET_TERMINAL, MA_EVENT_LOG
 };
-void app_menu_action(void *frontend, enum MenuAction);
+void app_menu_action(Frontend *frontend, enum MenuAction);
 
 /* Things pty.c needs from pterm.c */
-const char *get_x_display(void *frontend);
-int font_dimension(void *frontend, int which);/* 0 for width, 1 for height */
-int get_windowid(void *frontend, long *id);
+const char *get_x_display(Frontend *frontend);
+int font_dimension(Frontend *frontend, int which);/* 0 for width, 1 for height */
+int get_windowid(Frontend *frontend, long *id);
 
 /* Things gtkdlg.c needs from pterm.c */
 #ifdef MAY_REFER_TO_GTK_IN_HEADERS
-GtkWidget *get_window(void *frontend);
+GtkWidget *get_window(Frontend *frontend);
 enum DialogSlot {
     DIALOG_SLOT_RECONFIGURE,
     DIALOG_SLOT_NETWORK_PROMPT,
@@ -207,8 +207,8 @@ enum DialogSlot {
     DIALOG_SLOT_CONNECTION_FATAL,
     DIALOG_SLOT_LIMIT /* must remain last */
 };
-void register_dialog(void *frontend, enum DialogSlot slot, GtkWidget *dialog);
-void unregister_dialog(void *frontend, enum DialogSlot slot);
+void register_dialog(Frontend *frontend, enum DialogSlot slot, GtkWidget *dialog);
+void unregister_dialog(Frontend *frontend, enum DialogSlot slot);
 #endif
 
 /* Things pterm.c needs from gtkdlg.c */
diff --git a/unix/uxcons.c b/unix/uxcons.c
index e7f531dc..b4fecce1 100644
--- a/unix/uxcons.c
+++ b/unix/uxcons.c
@@ -63,15 +63,15 @@ void cleanup_exit(int code)
     exit(code);
 }
 
-void set_busy_status(void *frontend, int status)
+void set_busy_status(Frontend *frontend, int status)
 {
 }
 
-void update_specials_menu(void *frontend)
+void update_specials_menu(Frontend *frontend)
 {
 }
 
-void notify_remote_exit(void *frontend)
+void notify_remote_exit(Frontend *frontend)
 {
 }
 
@@ -113,7 +113,7 @@ static int block_and_read(int fd, void *buf, size_t len)
     return ret;
 }
 
-int verify_ssh_host_key(void *frontend, char *host, int port,
+int verify_ssh_host_key(Frontend *frontend, char *host, int port,
                         const char *keytype, char *keystr, char *fingerprint,
                         void (*callback)(void *ctx, int result), void *ctx)
 {
@@ -223,7 +223,7 @@ int verify_ssh_host_key(void *frontend, char *host, int port,
  * Ask whether the selected algorithm is acceptable (since it was
  * below the configured 'warn' threshold).
  */
-int askalg(void *frontend, const char *algtype, const char *algname,
+int askalg(Frontend *frontend, const char *algtype, const char *algname,
 	   void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msg[] =
@@ -270,7 +270,7 @@ int askalg(void *frontend, const char *algtype, const char *algname,
     }
 }
 
-int askhk(void *frontend, const char *algname, const char *betteralgs,
+int askhk(Frontend *frontend, const char *algname, const char *betteralgs,
           void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msg[] =
@@ -327,7 +327,7 @@ int askhk(void *frontend, const char *algname, const char *betteralgs,
  * Ask whether to wipe a session log file before writing to it.
  * Returns 2 for wipe, 1 for append, 0 for cancel (don't log).
  */
-int askappend(void *frontend, Filename *filename,
+int askappend(Frontend *frontend, Filename *filename,
 	      void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msgtemplate[] =
@@ -410,7 +410,7 @@ void console_provide_logctx(LogContext *logctx)
     console_logctx = logctx;
 }
 
-void logevent(void *frontend, const char *string)
+void logevent(Frontend *frontend, const char *string)
 {
     struct termios cf;
     if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE))
@@ -546,7 +546,7 @@ int console_get_userpass_input(prompts_t *p)
     return 1; /* success */
 }
 
-void frontend_keypress(void *handle)
+void frontend_keypress(Frontend *frontend)
 {
     /*
      * This is nothing but a stub, in console code.
diff --git a/unix/uxpgnt.c b/unix/uxpgnt.c
index 07248d39..6445fd57 100644
--- a/unix/uxpgnt.c
+++ b/unix/uxpgnt.c
@@ -42,7 +42,7 @@ void nonfatal(const char *p, ...)
     va_end(ap);
     fputc('\n', stderr);
 }
-void connection_fatal(void *frontend, const char *p, ...)
+void connection_fatal(Frontend *frontend, const char *p, ...)
 {
     va_list ap;
     fprintf(stderr, "FATAL ERROR: ");
@@ -93,7 +93,7 @@ FontSpec *platform_default_fontspec(const char *name) { return fontspec_new("");
 Filename *platform_default_filename(const char *name) { return filename_from_str(""); }
 char *x_get_default(const char *key) { return NULL; }
 void log_eventlog(LogContext *logctx, const char *event) {}
-int from_backend(void *frontend, int is_stderr, const void *data, int datalen)
+int from_backend(Frontend *fe, int is_stderr, const void *data, int datalen)
 { assert(!"only here to satisfy notional call from backend_socket_log"); }
 
 /*
diff --git a/unix/uxplink.c b/unix/uxplink.c
index 7bcac362..56bdf533 100644
--- a/unix/uxplink.c
+++ b/unix/uxplink.c
@@ -58,7 +58,7 @@ void nonfatal(const char *p, ...)
     fputc('\n', stderr);
     postmsg(&cf);
 }
-void connection_fatal(void *frontend, const char *p, ...)
+void connection_fatal(Frontend *frontend, const char *p, ...)
 {
     struct termios cf;
     va_list ap;
@@ -132,7 +132,7 @@ int term_ldisc(Terminal *term, int mode)
 {
     return FALSE;
 }
-void frontend_echoedit_update(void *frontend, int echo, int edit)
+void frontend_echoedit_update(Frontend *frontend, int echo, int edit)
 {
     /* Update stdin read mode to reflect changes in line discipline. */
     struct termios mode;
@@ -190,7 +190,7 @@ static char *get_ttychar(struct termios *t, int index)
     return dupprintf("^<%d>", c);
 }
 
-char *get_ttymode(void *frontend, const char *mode)
+char *get_ttymode(Frontend *frontend, const char *mode)
 {
     /*
      * Propagate appropriate terminal modes from the local terminal,
@@ -400,7 +400,7 @@ int try_output(int is_stderr)
     return bufchain_size(&stdout_data) + bufchain_size(&stderr_data);
 }
 
-int from_backend(void *frontend_handle, int is_stderr,
+int from_backend(Frontend *frontend, int is_stderr,
                  const void *data, int len)
 {
     if (is_stderr) {
@@ -413,7 +413,7 @@ int from_backend(void *frontend_handle, int is_stderr,
     }
 }
 
-int from_backend_untrusted(void *frontend_handle, const void *data, int len)
+int from_backend_untrusted(Frontend *frontend, const void *data, int len)
 {
     /*
      * No "untrusted" output should get here (the way the code is
@@ -423,7 +423,7 @@ int from_backend_untrusted(void *frontend_handle, const void *data, int len)
     return 0; /* not reached */
 }
 
-int from_backend_eof(void *frontend_handle)
+int from_backend_eof(Frontend *frontend)
 {
     assert(outgoingeof == EOF_NO);
     outgoingeof = EOF_PENDING;
diff --git a/unix/uxpty.c b/unix/uxpty.c
index 870e5156..a5c770d4 100644
--- a/unix/uxpty.c
+++ b/unix/uxpty.c
@@ -71,7 +71,7 @@ static int pty_signal_pipe[2] = { -1, -1 };   /* obviously bogus initial val */
 struct pty_tag {
     Conf *conf;
     int master_fd, slave_fd;
-    void *frontend;
+    Frontend *frontend;
     char name[FILENAME_MAX];
     pid_t child_pid;
     int term_width, term_height;
@@ -729,7 +729,7 @@ static void pty_uxsel_setup(Pty pty)
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static const char *pty_init(void *frontend, Backend **backend_handle,
+static const char *pty_init(Frontend *frontend, Backend **backend_handle,
                             Conf *conf, const char *host, int port,
                             char **realhost, int nodelay, int keepalive)
 {
diff --git a/unix/uxser.c b/unix/uxser.c
index e352f049..b02eb320 100644
--- a/unix/uxser.c
+++ b/unix/uxser.c
@@ -18,7 +18,7 @@
 #define SERIAL_MAX_BACKLOG 4096
 
 typedef struct serial_backend_data {
-    void *frontend;
+    Frontend *frontend;
     int fd;
     int finished;
     int inbufsize;
@@ -288,7 +288,7 @@ static const char *serial_configure(Serial serial, Conf *conf)
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static const char *serial_init(void *frontend_handle, Backend **backend_handle,
+static const char *serial_init(Frontend *frontend, Backend **backend_handle,
 			       Conf *conf,
 			       const char *host, int port, char **realhost,
                                int nodelay, int keepalive)
@@ -301,7 +301,7 @@ static const char *serial_init(void *frontend_handle, Backend **backend_handle,
     serial->backend.vt = &serial_backend;
     *backend_handle = &serial->backend;
 
-    serial->frontend = frontend_handle;
+    serial->frontend = frontend;
     serial->finished = FALSE;
     serial->inbufsize = 0;
     bufchain_init(&serial->output_data);
diff --git a/unix/uxsftp.c b/unix/uxsftp.c
index eb1329cf..a0d5c71e 100644
--- a/unix/uxsftp.c
+++ b/unix/uxsftp.c
@@ -66,7 +66,7 @@ Filename *platform_default_filename(const char *name)
 	return filename_from_str("");
 }
 
-char *get_ttymode(void *frontend, const char *mode) { return NULL; }
+char *get_ttymode(Frontend *frontend, const char *mode) { return NULL; }
 
 int get_userpass_input(prompts_t *p, bufchain *input)
 {
diff --git a/windows/wincons.c b/windows/wincons.c
index a7cbeeac..10367be8 100644
--- a/windows/wincons.c
+++ b/windows/wincons.c
@@ -30,11 +30,11 @@ void cleanup_exit(int code)
     exit(code);
 }
 
-void set_busy_status(void *frontend, int status)
+void set_busy_status(Frontend *frontend, int status)
 {
 }
 
-void notify_remote_exit(void *frontend)
+void notify_remote_exit(Frontend *frontend)
 {
 }
 
@@ -42,7 +42,7 @@ void timer_change_notify(unsigned long next)
 {
 }
 
-int verify_ssh_host_key(void *frontend, char *host, int port,
+int verify_ssh_host_key(Frontend *frontend, char *host, int port,
                         const char *keytype, char *keystr, char *fingerprint,
                         void (*callback)(void *ctx, int result), void *ctx)
 {
@@ -147,7 +147,7 @@ int verify_ssh_host_key(void *frontend, char *host, int port,
     }
 }
 
-void update_specials_menu(void *frontend)
+void update_specials_menu(Frontend *frontend)
 {
 }
 
@@ -155,7 +155,7 @@ void update_specials_menu(void *frontend)
  * Ask whether the selected algorithm is acceptable (since it was
  * below the configured 'warn' threshold).
  */
-int askalg(void *frontend, const char *algtype, const char *algname,
+int askalg(Frontend *frontend, const char *algtype, const char *algname,
 	   void (*callback)(void *ctx, int result), void *ctx)
 {
     HANDLE hin;
@@ -196,7 +196,7 @@ int askalg(void *frontend, const char *algtype, const char *algname,
     }
 }
 
-int askhk(void *frontend, const char *algname, const char *betteralgs,
+int askhk(Frontend *frontend, const char *algname, const char *betteralgs,
           void (*callback)(void *ctx, int result), void *ctx)
 {
     HANDLE hin;
@@ -247,7 +247,7 @@ int askhk(void *frontend, const char *algname, const char *betteralgs,
  * Ask whether to wipe a session log file before writing to it.
  * Returns 2 for wipe, 1 for append, 0 for cancel (don't log).
  */
-int askappend(void *frontend, Filename *filename,
+int askappend(Frontend *frontend, Filename *filename,
 	      void (*callback)(void *ctx, int result), void *ctx)
 {
     HANDLE hin;
@@ -340,7 +340,7 @@ void console_provide_logctx(LogContext *logctx)
     console_logctx = logctx;
 }
 
-void logevent(void *frontend, const char *string)
+void logevent(Frontend *frontend, const char *string)
 {
     log_eventlog(console_logctx, string);
 }
@@ -467,7 +467,7 @@ int console_get_userpass_input(prompts_t *p)
     return 1; /* success */
 }
 
-void frontend_keypress(void *handle)
+void frontend_keypress(Frontend *frontend)
 {
     /*
      * This is nothing but a stub, in console code.
diff --git a/windows/windlg.c b/windows/windlg.c
index 352ae1fc..05ddfdd2 100644
--- a/windows/windlg.c
+++ b/windows/windlg.c
@@ -761,7 +761,7 @@ int do_reconfig(HWND hwnd, int protcfginfo)
     return ret;
 }
 
-void logevent(void *frontend, const char *string)
+void logevent(Frontend *frontend, const char *string)
 {
     char timebuf[40];
     char **location;
@@ -813,7 +813,7 @@ void showabout(HWND hwnd)
     DialogBox(hinst, MAKEINTRESOURCE(IDD_ABOUTBOX), hwnd, AboutProc);
 }
 
-int verify_ssh_host_key(void *frontend, char *host, int port,
+int verify_ssh_host_key(Frontend *frontend, char *host, int port,
                         const char *keytype, char *keystr, char *fingerprint,
                         void (*callback)(void *ctx, int result), void *ctx)
 {
@@ -897,7 +897,7 @@ int verify_ssh_host_key(void *frontend, char *host, int port,
  * Ask whether the selected algorithm is acceptable (since it was
  * below the configured 'warn' threshold).
  */
-int askalg(void *frontend, const char *algtype, const char *algname,
+int askalg(Frontend *frontend, const char *algtype, const char *algname,
 	   void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char mbtitle[] = "%s Security Alert";
@@ -922,7 +922,7 @@ int askalg(void *frontend, const char *algtype, const char *algname,
 	return 0;
 }
 
-int askhk(void *frontend, const char *algname, const char *betteralgs,
+int askhk(Frontend *frontend, const char *algname, const char *betteralgs,
           void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char mbtitle[] = "%s Security Alert";
@@ -953,7 +953,7 @@ int askhk(void *frontend, const char *algname, const char *betteralgs,
  * Ask whether to wipe a session log file before writing to it.
  * Returns 2 for wipe, 1 for append, 0 for cancel (don't log).
  */
-int askappend(void *frontend, Filename *filename,
+int askappend(Frontend *frontend, Filename *filename,
 	      void (*callback)(void *ctx, int result), void *ctx)
 {
     static const char msgtemplate[] =
diff --git a/windows/window.c b/windows/window.c
index 0d29b136..eb0f5e01 100644
--- a/windows/window.c
+++ b/windows/window.c
@@ -231,16 +231,16 @@ const int share_can_be_downstream = TRUE;
 const int share_can_be_upstream = TRUE;
 
 /* Dummy routine, only required in plink. */
-void frontend_echoedit_update(void *frontend, int echo, int edit)
+void frontend_echoedit_update(Frontend *frontend, int echo, int edit)
 {
 }
 
-int frontend_is_utf8(void *frontend)
+int frontend_is_utf8(Frontend *frontend)
 {
     return ucsdata.line_codepage == CP_UTF8;
 }
 
-char *get_ttymode(void *frontend, const char *mode)
+char *get_ttymode(Frontend *frontend, const char *mode)
 {
     return term_get_ttymode(term, mode);
 }
@@ -946,7 +946,7 @@ static void update_savedsess_menu(void)
 /*
  * Update the Special Commands submenu.
  */
-void update_specials_menu(void *frontend)
+void update_specials_menu(Frontend *frontend)
 {
     HMENU new_menu;
     int i, j;
@@ -1052,7 +1052,7 @@ static void update_mouse_pointer(void)
     }
 }
 
-void set_busy_status(void *frontend, int status)
+void set_busy_status(Frontend *frontend, int status)
 {
     busy_status = status;
     update_mouse_pointer();
@@ -1061,7 +1061,7 @@ void set_busy_status(void *frontend, int status)
 /*
  * set or clear the "raw mouse message" mode
  */
-void set_raw_mouse_mode(void *frontend, int activate)
+void set_raw_mouse_mode(Frontend *frontend, int activate)
 {
     activate = activate && !conf_get_int(conf, CONF_no_mouse_rep);
     send_raw_mouse = activate;
@@ -1071,7 +1071,7 @@ void set_raw_mouse_mode(void *frontend, int activate)
 /*
  * Print a message box and close the connection.
  */
-void connection_fatal(void *frontend, const char *fmt, ...)
+void connection_fatal(Frontend *frontend, const char *fmt, ...)
 {
     va_list ap;
     char *stuff, morestuff[100];
@@ -1622,7 +1622,7 @@ static void deinit_fonts(void)
     }
 }
 
-void request_resize(void *frontend, int w, int h)
+void request_resize(Frontend *frontend, int w, int h)
 {
     int width, height;
 
@@ -1970,7 +1970,7 @@ static int is_alt_pressed(void)
 
 static int resizing;
 
-void notify_remote_exit(void *fe)
+void notify_remote_exit(Frontend *frontend)
 {
     int exitcode, close_on_exit;
 
@@ -3277,7 +3277,7 @@ static LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
  * helper software tracks the system caret, so we should arrange to
  * have one.)
  */
-void sys_cursor(void *frontend, int x, int y)
+void sys_cursor(Frontend *frontend, int x, int y)
 {
     int cx, cy;
 
@@ -4813,7 +4813,7 @@ static int TranslateKey(UINT message, WPARAM wParam, LPARAM lParam,
     return -1;
 }
 
-void set_title(void *frontend, char *title)
+void set_title(Frontend *frontend, char *title)
 {
     sfree(window_name);
     window_name = snewn(1 + strlen(title), char);
@@ -4822,7 +4822,7 @@ void set_title(void *frontend, char *title)
 	SetWindowText(hwnd, title);
 }
 
-void set_icon(void *frontend, char *title)
+void set_icon(Frontend *frontend, char *title)
 {
     sfree(icon_name);
     icon_name = snewn(1 + strlen(title), char);
@@ -4831,7 +4831,7 @@ void set_icon(void *frontend, char *title)
 	SetWindowText(hwnd, title);
 }
 
-void set_sbar(void *frontend, int total, int start, int page)
+void set_sbar(Frontend *frontend, int total, int start, int page)
 {
     SCROLLINFO si;
 
@@ -4849,7 +4849,7 @@ void set_sbar(void *frontend, int total, int start, int page)
 	SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
 }
 
-Context get_ctx(void *frontend)
+Context get_ctx(Frontend *frontend)
 {
     HDC hdc;
     if (hwnd) {
@@ -4879,7 +4879,7 @@ static void real_palette_set(int n, int r, int g, int b)
     }
 }
 
-int palette_get(void *frontend, int n, int *r, int *g, int *b)
+int palette_get(Frontend *frontend, int n, int *r, int *g, int *b)
 {
     if (n < 0 || n >= NALLCOLOURS)
 	return FALSE;
@@ -4889,7 +4889,7 @@ int palette_get(void *frontend, int n, int *r, int *g, int *b)
     return TRUE;
 }
 
-void palette_set(void *frontend, int n, int r, int g, int b)
+void palette_set(Frontend *frontend, int n, int r, int g, int b)
 {
     if (n >= 16)
 	n += 256 - 16;
@@ -4910,7 +4910,7 @@ void palette_set(void *frontend, int n, int r, int g, int b)
     }
 }
 
-void palette_reset(void *frontend)
+void palette_reset(Frontend *frontend)
 {
     int i;
 
@@ -4939,7 +4939,7 @@ void palette_reset(void *frontend)
     }
 }
 
-void write_aclip(void *frontend, int clipboard,
+void write_aclip(Frontend *frontend, int clipboard,
                  char *data, int len, int must_deselect)
 {
     HGLOBAL clipdata;
@@ -4987,7 +4987,7 @@ int cmpCOLORREF(void *va, void *vb)
 /*
  * Note: unlike write_aclip() this will not append a nul.
  */
-void write_clip(void *frontend, int clipboard,
+void write_clip(Frontend *frontend, int clipboard,
                 wchar_t *data, int *attr, truecolour *truecolour, int len,
                 int must_deselect)
 {
@@ -5458,7 +5458,7 @@ static void process_clipdata(HGLOBAL clipdata, int unicode)
     sfree(clipboard_contents);
 }
 
-void frontend_request_paste(void *frontend, int clipboard)
+void frontend_request_paste(Frontend *frontend, int clipboard)
 {
     assert(clipboard == CLIP_SYSTEM);
 
@@ -5488,7 +5488,7 @@ void frontend_request_paste(void *frontend, int clipboard)
  * Move `lines' lines from position `from' to position `to' in the
  * window.
  */
-void optimised_move(void *frontend, int to, int from, int lines)
+void optimised_move(Frontend *frontend, int to, int from, int lines)
 {
     RECT r;
     int min, max;
@@ -5618,7 +5618,7 @@ static void flash_window(int mode)
 /*
  * Beep.
  */
-void do_beep(void *frontend, int mode)
+void do_beep(Frontend *frontend, int mode)
 {
     if (mode == BELL_DEFAULT) {
 	/*
@@ -5680,7 +5680,7 @@ void do_beep(void *frontend, int mode)
  * Minimise or restore the window in response to a server-side
  * request.
  */
-void set_iconic(void *frontend, int iconic)
+void set_iconic(Frontend *frontend, int iconic)
 {
     if (IsIconic(hwnd)) {
 	if (!iconic)
@@ -5694,7 +5694,7 @@ void set_iconic(void *frontend, int iconic)
 /*
  * Move the window in response to a server-side request.
  */
-void move_window(void *frontend, int x, int y)
+void move_window(Frontend *frontend, int x, int y)
 {
     int resize_action = conf_get_int(conf, CONF_resize_action);
     if (resize_action == RESIZE_DISABLED || 
@@ -5709,7 +5709,7 @@ void move_window(void *frontend, int x, int y)
  * Move the window to the top or bottom of the z-order in response
  * to a server-side request.
  */
-void set_zorder(void *frontend, int top)
+void set_zorder(Frontend *frontend, int top)
 {
     if (conf_get_int(conf, CONF_alwaysontop))
 	return;			       /* ignore */
@@ -5720,7 +5720,7 @@ void set_zorder(void *frontend, int top)
 /*
  * Refresh the window in response to a server-side request.
  */
-void refresh_window(void *frontend)
+void refresh_window(Frontend *frontend)
 {
     InvalidateRect(hwnd, NULL, TRUE);
 }
@@ -5729,7 +5729,7 @@ void refresh_window(void *frontend)
  * Maximise or restore the window in response to a server-side
  * request.
  */
-void set_zoomed(void *frontend, int zoomed)
+void set_zoomed(Frontend *frontend, int zoomed)
 {
     if (IsZoomed(hwnd)) {
         if (!zoomed)
@@ -5743,7 +5743,7 @@ void set_zoomed(void *frontend, int zoomed)
 /*
  * Report whether the window is iconic, for terminal reports.
  */
-int is_iconic(void *frontend)
+int is_iconic(Frontend *frontend)
 {
     return IsIconic(hwnd);
 }
@@ -5751,7 +5751,7 @@ int is_iconic(void *frontend)
 /*
  * Report the window's position, for terminal reports.
  */
-void get_window_pos(void *frontend, int *x, int *y)
+void get_window_pos(Frontend *frontend, int *x, int *y)
 {
     RECT r;
     GetWindowRect(hwnd, &r);
@@ -5762,7 +5762,7 @@ void get_window_pos(void *frontend, int *x, int *y)
 /*
  * Report the window's pixel size, for terminal reports.
  */
-void get_window_pixels(void *frontend, int *x, int *y)
+void get_window_pixels(Frontend *frontend, int *x, int *y)
 {
     RECT r;
     GetWindowRect(hwnd, &r);
@@ -5773,7 +5773,7 @@ void get_window_pixels(void *frontend, int *x, int *y)
 /*
  * Return the window or icon title.
  */
-char *get_window_title(void *frontend, int icon)
+char *get_window_title(Frontend *frontend, int icon)
 {
     return icon ? icon_name : window_name;
 }
@@ -5906,7 +5906,7 @@ static void flip_full_screen()
     }
 }
 
-void frontend_keypress(void *handle)
+void frontend_keypress(Frontend *frontend)
 {
     /*
      * Keypress termination in non-Close-On-Exit mode is not
@@ -5917,17 +5917,17 @@ void frontend_keypress(void *handle)
     return;
 }
 
-int from_backend(void *frontend, int is_stderr, const void *data, int len)
+int from_backend(Frontend *frontend, int is_stderr, const void *data, int len)
 {
     return term_data(term, is_stderr, data, len);
 }
 
-int from_backend_untrusted(void *frontend, const void *data, int len)
+int from_backend_untrusted(Frontend *frontend, const void *data, int len)
 {
     return term_data_untrusted(term, data, len);
 }
 
-int from_backend_eof(void *frontend)
+int from_backend_eof(Frontend *frontend)
 {
     return TRUE;   /* do respond to incoming EOF with outgoing */
 }
diff --git a/windows/winplink.c b/windows/winplink.c
index 455b18a7..c156d740 100644
--- a/windows/winplink.c
+++ b/windows/winplink.c
@@ -45,7 +45,7 @@ void nonfatal(const char *p, ...)
     va_end(ap);
     fputc('\n', stderr);
 }
-void connection_fatal(void *frontend, const char *p, ...)
+void connection_fatal(Frontend *frontend, const char *p, ...)
 {
     va_list ap;
     fprintf(stderr, "FATAL ERROR: ");
@@ -83,7 +83,7 @@ int term_ldisc(Terminal *term, int mode)
 {
     return FALSE;
 }
-void frontend_echoedit_update(void *frontend, int echo, int edit)
+void frontend_echoedit_update(Frontend *frontend, int echo, int edit)
 {
     /* Update stdin read mode to reflect changes in line discipline. */
     DWORD mode;
@@ -100,9 +100,9 @@ void frontend_echoedit_update(void *frontend, int echo, int edit)
     SetConsoleMode(inhandle, mode);
 }
 
-char *get_ttymode(void *frontend, const char *mode) { return NULL; }
+char *get_ttymode(Frontend *frontend, const char *mode) { return NULL; }
 
-int from_backend(void *frontend_handle, int is_stderr,
+int from_backend(Frontend *frontend, int is_stderr,
 		 const void *data, int len)
 {
     if (is_stderr) {
@@ -114,7 +114,7 @@ int from_backend(void *frontend_handle, int is_stderr,
     return handle_backlog(stdout_handle) + handle_backlog(stderr_handle);
 }
 
-int from_backend_untrusted(void *frontend_handle, const void *data, int len)
+int from_backend_untrusted(Frontend *frontend, const void *data, int len)
 {
     /*
      * No "untrusted" output should get here (the way the code is
@@ -124,7 +124,7 @@ int from_backend_untrusted(void *frontend_handle, const void *data, int len)
     return 0; /* not reached */
 }
 
-int from_backend_eof(void *frontend_handle)
+int from_backend_eof(Frontend *frontend)
 {
     handle_write_eof(stdout_handle);
     return FALSE;   /* do not respond to incoming EOF with outgoing */
diff --git a/windows/winser.c b/windows/winser.c
index 1efac931..2a42ce21 100644
--- a/windows/winser.c
+++ b/windows/winser.c
@@ -13,7 +13,7 @@
 typedef struct serial_backend_data {
     HANDLE port;
     struct handle *out, *in;
-    void *frontend;
+    Frontend *frontend;
     int bufsize;
     long clearbreak_time;
     int break_in_progress;
@@ -199,7 +199,7 @@ static const char *serial_configure(Serial serial, HANDLE serport, Conf *conf)
  * Also places the canonical host name into `realhost'. It must be
  * freed by the caller.
  */
-static const char *serial_init(void *frontend_handle, Backend **backend_handle,
+static const char *serial_init(Frontend *frontend, Backend **backend_handle,
 			       Conf *conf, const char *host, int port,
 			       char **realhost, int nodelay, int keepalive)
 {
@@ -216,7 +216,7 @@ static const char *serial_init(void *frontend_handle, Backend **backend_handle,
     serial->backend.vt = &serial_backend;
     *backend_handle = &serial->backend;
 
-    serial->frontend = frontend_handle;
+    serial->frontend = frontend;
 
     serline = conf_get_str(conf, CONF_serline);
     {
diff --git a/windows/winsftp.c b/windows/winsftp.c
index e9d5d4cb..580e8d95 100644
--- a/windows/winsftp.c
+++ b/windows/winsftp.c
@@ -13,7 +13,7 @@
 #include "int64.h"
 #include "winsecur.h"
 
-char *get_ttymode(void *frontend, const char *mode) { return NULL; }
+char *get_ttymode(Frontend *frontend, const char *mode) { return NULL; }
 
 int get_userpass_input(prompts_t *p, bufchain *input)
 {
diff --git a/windows/winstuff.h b/windows/winstuff.h
index 87dc48b6..1ecec333 100644
--- a/windows/winstuff.h
+++ b/windows/winstuff.h
@@ -247,7 +247,7 @@ GLOBAL LogContext *logctx;
  * which takes the data string in the system code page instead of
  * Unicode.
  */
-void write_aclip(void *frontend, int clipboard, char *, int, int);
+void write_aclip(Frontend *frontend, int clipboard, char *, int, int);
 
 #define WM_NETEVENT  (WM_APP + 5)