1 files changed, 15 insertions, 0 deletions

diff --git a/src/w32fns.c b/src/w32fns.c
index 0eb720e1cbe..f5e5b33556c 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -276,6 +276,8 @@ static struct
 } kbdhook;
 typedef HWND (WINAPI *GetConsoleWindow_Proc) (void);
 
+typedef BOOL (WINAPI *IsDebuggerPresent_Proc) (void);
+
 /* stdin, from w32console.c */
 extern HANDLE keyboard_handle;
 
@@ -2303,6 +2305,19 @@ setup_w32_kbdhook (void)
 {
   kbdhook.hook_count++;
 
+  /* This hook gets in the way of debugging, since when Emacs stops,
+     its input thread stops, and there's nothing to process keyboard
+     events, whereas this hook is global, and is invoked in the
+     context of the thread that installed it.  So we don't install the
+     hook if the process is being debugged. */
+  if (w32_kbdhook_active)
+    {
+      IsDebuggerPresent_Proc is_debugger_present = (IsDebuggerPresent_Proc)
+        GetProcAddress (GetModuleHandle ("kernel32.dll"), "IsDebuggerPresent");
+      if (is_debugger_present && is_debugger_present ())
+        return;
+    }
+
   /* Hooking is only available on NT architecture systems, as
      indicated by the w32_kbdhook_active variable.  */
   if (kbdhook.hook_count == 1 && w32_kbdhook_active)