(sys_select): Always wait on interrupt_handle, so that

user can break out of `accept-process-input' (for instance) by typing C-g.

diff --git a/src/w32proc.c b/src/w32proc.c
index a416403b74b85b597a9cf3f62a4fe80f3f87bcdd..ccb47ccc89501f0e35467003c88176ac679d44d0 100644 (file)
--- a/src/w32proc.c
+++ b/src/w32proc.c
@@ -987,10 +987,20 @@ sys_spawnve (int mode, char *cmdname, char **argv, char **envp)
    children to be created without a corresponding pipe handle from which
    to read output, we wait separately on the process handles as well as
    the char_avail events for each process pipe.  We only call
-   wait/reap_process when the process actually terminates.  */
+   wait/reap_process when the process actually terminates.
+
+   To reduce the number of places in which Emacs can be hung such that
+   C-g is not able to interrupt it, we always wait on interrupt_handle
+   (which is signalled by the input thread when C-g is detected).  If we
+   detect that we were woken up by C-g, we return -1 with errno set to
+   EINTR as on Unix.  */
 
 /* From ntterm.c */
 extern HANDLE keyboard_handle;
+
+/* From w32xfns.c */
+extern HANDLE interrupt_handle;
+
 /* From process.c */
 extern int proc_buffered_char[];
 
@@ -1025,9 +1035,13 @@ sys_select (int nfds, SELECT_TYPE *rfds, SELECT_TYPE *wfds, SELECT_TYPE *efds,
   orfds = *rfds;
   FD_ZERO (rfds);
   nr = 0;
+
+  /* Always wait on interrupt_handle, to detect C-g (quit).  */
+  wait_hnd[0] = interrupt_handle;
+  fdindex[0] = -1;
   
   /* Build a list of pipe handles to wait on.  */
-  nh = 0;
+  nh = 1;
   for (i = 0; i < nfds; i++)
     if (FD_ISSET (i, &orfds))
       {
@@ -1212,6 +1226,12 @@ count_children:
              dead_child = NULL;
            }
        }
+      else if (fdindex[active] == -1)
+       {
+         /* Quit (C-g) was detected.  */
+         errno = EINTR;
+         return -1;
+       }
       else if (fdindex[active] == 0)
        {
          /* Keyboard input available */