diff --git a/terminal/terminal.c b/terminal/terminal.c
index ad309436..0c52fc6e 100644
--- a/terminal/terminal.c
+++ b/terminal/terminal.c
@@ -3185,22 +3185,18 @@ static void toggle_mode(Terminal *term, int mode, int query, bool state)
 }
 
 /*
- * Process an OSC sequence: set window title or icon name.
+ * Process an OSC or similar sequence, with a whole embedded string,
+ * like setting the window title or icon name.
  */
 static void do_osc(Terminal *term)
 {
-    if (term->osc_is_apc) {
-        /* This OSC was really an APC, and we don't support that
-         * sequence at all. We only recognise it in order to ignore it
-         * and filter it out of input. */
-        return;
-    }
-
-    if (term->osc_w) {
+    switch (term->osc_type) {
+      case OSCLIKE_OSC_W:
         while (term->osc_strlen--)
             term->wordness[(unsigned char)term->osc_string[term->osc_strlen]] =
                 term->esc_args[0];
-    } else {
+        break;
+      case OSCLIKE_OSC:
         term->osc_string[term->osc_strlen] = '\0';
         switch (term->esc_args[0]) {
           case 0:
@@ -3242,6 +3238,11 @@ static void do_osc(Terminal *term)
             }
             break;
         }
+        break;
+      default:
+        /* APC, SOS and PM are recognised as control sequences but
+         * ignored. PuTTY implements no support for any of them. */
+        break;
     }
 }
 
@@ -4122,7 +4123,7 @@ static void term_out(Terminal *term, bool called_from_term_data)
                     /* Compatibility is nasty here, xterm, linux, decterm yuk! */
                     compatibility(OTHER);
                     term->termstate = SEEN_OSC;
-                    term->osc_is_apc = false;
+                    term->osc_type = OSCLIKE_OSC;
                     term->osc_strlen = 0;
                     term->esc_args[0] = 0;
                     term->esc_nargs = 1;
@@ -4130,15 +4131,16 @@ static void term_out(Terminal *term, bool called_from_term_data)
                   case 'X':             /* SOS: Start of String */
                   case '^':             /* PM: privacy message */
                   case '_':             /* APC: application program command */
-                    /* SOS, PM, and APC sequences are just a string, terminated by
-                     * ST or (I've observed in practice for APC) ^G. That is,
-                     * they have the same termination convention as
-                     * OSC. So we handle them by going straight into
-                     * OSC_STRING state and setting a flag indicating
-                     * that it's not really an OSC. */
+                    /* SOS, PM, and APC sequences are just a string, terminated
+                     * by ST or (I've observed in practice for APC) ^G. That
+                     * is, they have the same termination convention as OSC. So
+                     * we handle them by going straight into OSC_STRING state
+                     * and setting a flag indicating that it's not really an
+                     * OSC. */
                     compatibility(OTHER);
                     term->termstate = SEEN_OSC;
-                    term->osc_is_apc = true;
+                    term->osc_type = (c == 'X' ? OSCLIKE_SOS :
+                                      c == '^' ? OSCLIKE_PM : OSCLIKE_APC);
                     term->osc_strlen = 0;
                     term->esc_args[0] = 0;
                     term->esc_nargs = 1;
@@ -5247,7 +5249,7 @@ static void term_out(Terminal *term, bool called_from_term_data)
                     }
                 break;
               case SEEN_OSC:
-                term->osc_w = false;
+                term->osc_type = OSCLIKE_OSC;
                 switch (c) {
                   case 'P':            /* Linux palette sequence */
                     term->termstate = SEEN_OSC_P;
@@ -5260,7 +5262,7 @@ static void term_out(Terminal *term, bool called_from_term_data)
                     break;
                   case 'W':            /* word-set */
                     term->termstate = SEEN_OSC_W;
-                    term->osc_w = true;
+                    term->osc_type = OSCLIKE_OSC_W;
                     break;
                   case '0':
                   case '1':
diff --git a/terminal/terminal.h b/terminal/terminal.h
index e5bb16ae..0e7ab771 100644
--- a/terminal/terminal.h
+++ b/terminal/terminal.h
@@ -73,6 +73,14 @@ struct term_utf8_decode {
 
 struct term_userpass_state;
 
+typedef enum {
+    OSCLIKE_OSC,
+    OSCLIKE_OSC_W,
+    OSCLIKE_APC,
+    OSCLIKE_SOS,
+    OSCLIKE_PM,
+} OscType;
+
 struct terminal_tag {
 
     int compatibility_level;
@@ -183,10 +191,9 @@ struct terminal_tag {
 #define ANSI_QUE(x)     ANSI(x,1)
 
 #define OSC_STR_MAX 2048
-    bool osc_is_apc;
+    OscType osc_type;
     int osc_strlen;
     char osc_string[OSC_STR_MAX + 1];
-    bool osc_w;
 
     char id_string[1024];