1 files changed, 3 insertions, 0 deletions

diff --git a/src/keyboard.h b/src/keyboard.h
index 96ac7d2e856..f8d8f789c08 100644
--- a/src/keyboard.h
+++ b/src/keyboard.h
@@ -190,6 +190,9 @@ extern EMACS_INT num_nonmacro_input_events;
 /* Nonzero means polling for input is temporarily suppressed.  */
 extern int poll_suppress_count;
 
+/* Nonzero if we are executing from the SIGIO signal handler. */
+extern int in_sighandler;
+
 /* Keymap mapping ASCII function key sequences onto their preferred forms.
    Initialized by the terminal-specific lisp files.  */
 extern Lisp_Object Vfunction_key_map;