diff --git a/defs.h b/defs.h
index bfdf345d..f1d73fb5 100644
--- a/defs.h
+++ b/defs.h
@@ -44,6 +44,8 @@ typedef struct SockAddr_tag *SockAddr;
 typedef struct Socket_vtable Socket_vtable;
 typedef struct Plug_vtable Plug_vtable;
 
+typedef struct Ldisc_tag Ldisc;
+
 /* Note indirection: for historical reasons (it used to be closer to
  * the OS socket type), the type that most code uses for a socket is
  * 'Socket', not 'Socket *'. So an implementation of Socket or Plug
diff --git a/fuzzterm.c b/fuzzterm.c
index 21246069..cdefb0d9 100644
--- a/fuzzterm.c
+++ b/fuzzterm.c
@@ -71,8 +71,8 @@ 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 ldisc_send(void *handle, const void *buf, int len, int interactive) {}
-void ldisc_echoedit_update(void *handle) {}
+void ldisc_send(Ldisc *ldisc, const void *buf, int len, int interactive) {}
+void ldisc_echoedit_update(Ldisc *ldisc) {}
 Context get_ctx(void *frontend) { 
     static char x;
 
diff --git a/ldisc.c b/ldisc.c
index 06c5e90f..ba90e1d0 100644
--- a/ldisc.c
+++ b/ldisc.c
@@ -22,12 +22,12 @@
                       (ldisc->back->ldisc(ldisc->backhandle, LD_EDIT) || \
 			   term_ldisc(ldisc->term, LD_EDIT))))
 
-static void c_write(Ldisc ldisc, const void *buf, int len)
+static void c_write(Ldisc *ldisc, const void *buf, int len)
 {
     from_backend(ldisc->frontend, 0, buf, len);
 }
 
-static int plen(Ldisc ldisc, unsigned char c)
+static int plen(Ldisc *ldisc, unsigned char c)
 {
     if ((c >= 32 && c <= 126) || (c >= 160 && !in_utf(ldisc->term)))
 	return 1;
@@ -42,7 +42,7 @@ static int plen(Ldisc ldisc, unsigned char c)
 	return 4;		       /* <XY> hex representation */
 }
 
-static void pwrite(Ldisc ldisc, unsigned char c)
+static void pwrite(Ldisc *ldisc, unsigned char c)
 {
     if ((c >= 32 && c <= 126) ||
 	(!in_utf(ldisc->term) && c >= 0xA0) ||
@@ -60,7 +60,7 @@ static void pwrite(Ldisc ldisc, unsigned char c)
     }
 }
 
-static int char_start(Ldisc ldisc, unsigned char c)
+static int char_start(Ldisc *ldisc, unsigned char c)
 {
     if (in_utf(ldisc->term))
 	return (c < 0x80 || c >= 0xC0);
@@ -68,7 +68,7 @@ static int char_start(Ldisc ldisc, unsigned char c)
 	return 1;
 }
 
-static void bsb(Ldisc ldisc, int n)
+static void bsb(Ldisc *ldisc, int n)
 {
     while (n--)
 	c_write(ldisc, "\010 \010", 3);
@@ -77,11 +77,11 @@ static void bsb(Ldisc ldisc, int n)
 #define CTRL(x) (x^'@')
 #define KCTRL(x) ((x^'@') | 0x100)
 
-void *ldisc_create(Conf *conf, Terminal *term,
+Ldisc *ldisc_create(Conf *conf, Terminal *term,
 		   Backend *back, void *backhandle,
 		   void *frontend)
 {
-    Ldisc ldisc = snew(struct ldisc_tag);
+    Ldisc *ldisc = snew(Ldisc);
 
     ldisc->buf = NULL;
     ldisc->buflen = 0;
@@ -104,10 +104,8 @@ void *ldisc_create(Conf *conf, Terminal *term,
     return ldisc;
 }
 
-void ldisc_configure(void *handle, Conf *conf)
+void ldisc_configure(Ldisc *ldisc, Conf *conf)
 {
-    Ldisc ldisc = (Ldisc) handle;
-
     ldisc->telnet_keyboard = conf_get_int(conf, CONF_telnet_keyboard);
     ldisc->telnet_newline = conf_get_int(conf, CONF_telnet_newline);
     ldisc->protocol = conf_get_int(conf, CONF_protocol);
@@ -115,10 +113,8 @@ void ldisc_configure(void *handle, Conf *conf)
     ldisc->localedit = conf_get_int(conf, CONF_localedit);
 }
 
-void ldisc_free(void *handle)
+void ldisc_free(Ldisc *ldisc)
 {
-    Ldisc ldisc = (Ldisc) handle;
-
     if (ldisc->term)
 	ldisc->term->ldisc = NULL;
     if (ldisc->back)
@@ -128,16 +124,14 @@ void ldisc_free(void *handle)
     sfree(ldisc);
 }
 
-void ldisc_echoedit_update(void *handle)
+void ldisc_echoedit_update(Ldisc *ldisc)
 {
-    Ldisc ldisc = (Ldisc) handle;
     frontend_echoedit_update(ldisc->frontend, ECHOING, EDITING);
 }
 
-void ldisc_send(void *handle, const void *vbuf, int len, int interactive)
+void ldisc_send(Ldisc *ldisc, const void *vbuf, int len, int interactive)
 {
     const char *buf = (const char *)vbuf;
-    Ldisc ldisc = (Ldisc) handle;
     int keyflag = 0;
 
     assert(ldisc->term);
diff --git a/ldisc.h b/ldisc.h
index 5dbe2a76..44f5772f 100644
--- a/ldisc.h
+++ b/ldisc.h
@@ -8,7 +8,7 @@
 #ifndef PUTTY_LDISC_H
 #define PUTTY_LDISC_H
 
-typedef struct ldisc_tag {
+struct Ldisc_tag {
     Terminal *term;
     Backend *back;
     void *backhandle;
@@ -21,6 +21,6 @@ typedef struct ldisc_tag {
 
     char *buf;
     int buflen, bufsiz, quotenext;
-} *Ldisc;
+};
 
 #endif /* PUTTY_LDISC_H */
diff --git a/ldiscucs.c b/ldiscucs.c
index 1634bc43..6c943a09 100644
--- a/ldiscucs.c
+++ b/ldiscucs.c
@@ -12,10 +12,9 @@
 #include "terminal.h"
 #include "ldisc.h"
 
-void lpage_send(void *handle,
+void lpage_send(Ldisc *ldisc,
 		int codepage, const char *buf, int len, int interactive)
 {
-    Ldisc ldisc = (Ldisc)handle;
     wchar_t *widebuffer = 0;
     int widesize = 0;
     int wclen;
@@ -34,9 +33,8 @@ void lpage_send(void *handle,
     sfree(widebuffer);
 }
 
-void luni_send(void *handle, const wchar_t *widebuf, int len, int interactive)
+void luni_send(Ldisc *ldisc, const wchar_t *widebuf, int len, int interactive)
 {
-    Ldisc ldisc = (Ldisc)handle;
     int ratio = (in_utf(ldisc->term))?3:1;
     char *linebuffer;
     int linesize;
diff --git a/pscp.c b/pscp.c
index 22cbf57e..964e2443 100644
--- a/pscp.c
+++ b/pscp.c
@@ -60,7 +60,7 @@ const char *const appname = "PSCP";
  */
 #define MAX_SCP_BUFSIZE 16384
 
-void ldisc_echoedit_update(void *handle) { }
+void ldisc_echoedit_update(Ldisc *ldisc) { }
 
 static void tell_char(FILE *stream, char c)
 {
diff --git a/psftp.c b/psftp.c
index 46eeeb40..b28c0976 100644
--- a/psftp.c
+++ b/psftp.c
@@ -2483,7 +2483,7 @@ void connection_fatal(void *frontend, const char *fmt, ...)
     cleanup_exit(1);
 }
 
-void ldisc_echoedit_update(void *handle) { }
+void ldisc_echoedit_update(Ldisc *ldisc) { }
 
 /*
  * In psftp, all agent requests should be synchronous, so this is a
diff --git a/putty.h b/putty.h
index 844c6fa1..042f66c5 100644
--- a/putty.h
+++ b/putty.h
@@ -461,7 +461,7 @@ struct backend_tag {
      * may be lost. */
     int (*sendok) (void *handle);
     int (*ldisc) (void *handle, int);
-    void (*provide_ldisc) (void *handle, void *ldisc);
+    void (*provide_ldisc) (void *handle, Ldisc *ldisc);
     void (*provide_logctx) (void *handle, void *logctx);
     /*
      * back->unthrottle() tells the back end that the front end
@@ -1174,18 +1174,18 @@ extern Backend ssh_backend;
 /*
  * Exports from ldisc.c.
  */
-void *ldisc_create(Conf *, Terminal *, Backend *, void *, void *);
-void ldisc_configure(void *, Conf *);
-void ldisc_free(void *);
-void ldisc_send(void *handle, const void *buf, int len, int interactive);
-void ldisc_echoedit_update(void *handle);
+Ldisc *ldisc_create(Conf *, Terminal *, Backend *, void *, void *);
+void ldisc_configure(Ldisc *, Conf *);
+void ldisc_free(Ldisc *);
+void ldisc_send(Ldisc *, const void *buf, int len, int interactive);
+void ldisc_echoedit_update(Ldisc *);
 
 /*
  * Exports from ldiscucs.c.
  */
-void lpage_send(void *, int codepage, const char *buf, int len,
+void lpage_send(Ldisc *, int codepage, const char *buf, int len,
                 int interactive);
-void luni_send(void *, const wchar_t * widebuf, int len, int interactive);
+void luni_send(Ldisc *, const wchar_t * widebuf, int len, int interactive);
 
 /*
  * Exports from sshrand.c.
diff --git a/raw.c b/raw.c
index 67d34601..58a500c7 100644
--- a/raw.c
+++ b/raw.c
@@ -274,7 +274,7 @@ static int raw_ldisc(void *handle, int option)
     return 0;
 }
 
-static void raw_provide_ldisc(void *handle, void *ldisc)
+static void raw_provide_ldisc(void *handle, Ldisc *ldisc)
 {
     /* This is a stub. */
 }
diff --git a/rlogin.c b/rlogin.c
index 9156340c..7f9093e4 100644
--- a/rlogin.c
+++ b/rlogin.c
@@ -366,7 +366,7 @@ static int rlogin_ldisc(void *handle, int option)
     return 0;
 }
 
-static void rlogin_provide_ldisc(void *handle, void *ldisc)
+static void rlogin_provide_ldisc(void *handle, Ldisc *ldisc)
 {
     /* This is a stub. */
 }
diff --git a/ssh.c b/ssh.c
index 4c237e31..d02b7321 100644
--- a/ssh.c
+++ b/ssh.c
@@ -700,7 +700,7 @@ struct ssh_tag {
 
     const Plug_vtable *plugvt;
 
-    void *ldisc;
+    Ldisc *ldisc;
     void *logctx;
 
     unsigned char session_key[32];
@@ -11428,7 +11428,7 @@ static int ssh_ldisc(void *handle, int option)
     return FALSE;
 }
 
-static void ssh_provide_ldisc(void *handle, void *ldisc)
+static void ssh_provide_ldisc(void *handle, Ldisc *ldisc)
 {
     Ssh ssh = (Ssh) handle;
     ssh->ldisc = ldisc;
diff --git a/telnet.c b/telnet.c
index 6fe509dc..0f958b50 100644
--- a/telnet.c
+++ b/telnet.c
@@ -175,7 +175,7 @@ typedef struct telnet_tag {
     int closed_on_socket_error;
 
     void *frontend;
-    void *ldisc;
+    Ldisc *ldisc;
     int term_width, term_height;
 
     int opt_states[NUM_OPTS];
@@ -1059,7 +1059,7 @@ static int telnet_ldisc(void *handle, int option)
     return FALSE;
 }
 
-static void telnet_provide_ldisc(void *handle, void *ldisc)
+static void telnet_provide_ldisc(void *handle, Ldisc *ldisc)
 {
     Telnet telnet = (Telnet) handle;
     telnet->ldisc = ldisc;
diff --git a/terminal.h b/terminal.h
index ba4a07f6..3eb60939 100644
--- a/terminal.h
+++ b/terminal.h
@@ -230,7 +230,7 @@ struct terminal_tag {
     void (*resize_fn)(void *, int, int);
     void *resize_ctx;
 
-    void *ldisc;
+    Ldisc *ldisc;
 
     void *frontend;
 
diff --git a/testback.c b/testback.c
index a84caee0..d84c77db 100644
--- a/testback.c
+++ b/testback.c
@@ -49,7 +49,7 @@ static int null_connected(void *);
 static int null_exitcode(void *);
 static int null_sendok(void *);
 static int null_ldisc(void *, int);
-static void null_provide_ldisc(void *, void *);
+static void null_provide_ldisc(void *, Ldisc *);
 static void null_provide_logctx(void *, void *);
 static void null_unthrottle(void *, int);
 static int null_cfg_info(void *);
@@ -157,7 +157,7 @@ static int null_ldisc(void *handle, int option) {
     return 0;
 }
 
-static void null_provide_ldisc (void *handle, void *ldisc) {
+static void null_provide_ldisc (void *handle, Ldisc *ldisc) {
 
 }
 
diff --git a/unix/gtkwin.c b/unix/gtkwin.c
index 5b84c7c9..e28146b4 100644
--- a/unix/gtkwin.c
+++ b/unix/gtkwin.c
@@ -158,7 +158,7 @@ struct gui_data {
     char *wintitle;
     char *icontitle;
     int master_fd, master_func_id;
-    void *ldisc;
+    Ldisc *ldisc;
     Backend *back;
     void *backhandle;
     Terminal *term;
diff --git a/unix/uxpty.c b/unix/uxpty.c
index 7aaad8ac..9df61532 100644
--- a/unix/uxpty.c
+++ b/unix/uxpty.c
@@ -1206,7 +1206,7 @@ static int pty_ldisc(void *handle, int option)
     return 0;			       /* neither editing nor echoing */
 }
 
-static void pty_provide_ldisc(void *handle, void *ldisc)
+static void pty_provide_ldisc(void *handle, Ldisc *ldisc)
 {
     /* Pty pty = (Pty)handle; */
     /* This is a stub. */
diff --git a/unix/uxser.c b/unix/uxser.c
index e77f797a..558cf015 100644
--- a/unix/uxser.c
+++ b/unix/uxser.c
@@ -544,7 +544,7 @@ static int serial_ldisc(void *handle, int option)
     return 0;
 }
 
-static void serial_provide_ldisc(void *handle, void *ldisc)
+static void serial_provide_ldisc(void *handle, Ldisc *ldisc)
 {
     /* This is a stub. */
 }
diff --git a/windows/window.c b/windows/window.c
index 1a7bb472..80b94201 100644
--- a/windows/window.c
+++ b/windows/window.c
@@ -125,7 +125,7 @@ static int caret_x = -1, caret_y = -1;
 
 static int kbd_codepage;
 
-static void *ldisc;
+static Ldisc *ldisc;
 static Backend *back;
 static void *backhandle;
 
diff --git a/windows/winser.c b/windows/winser.c
index 976f8955..2dd45fac 100644
--- a/windows/winser.c
+++ b/windows/winser.c
@@ -409,7 +409,7 @@ static int serial_ldisc(void *handle, int option)
     return 0;
 }
 
-static void serial_provide_ldisc(void *handle, void *ldisc)
+static void serial_provide_ldisc(void *handle, Ldisc *ldisc)
 {
     /* This is a stub. */
 }