diff --git a/src/s/irix4-0.h b/src/s/irix4-0.h
index 3a28bbf59c8..7f8cb356ee6 100644
--- a/src/s/irix4-0.h
+++ b/src/s/irix4-0.h
@@ -25,7 +25,7 @@
 /* No need to get the pty name at all.  */
 #define PTY_NAME_SPRINTF
 #ifdef emacs
-char *_get_pty();
+char *_getpty();
 #endif
 /* We need only try once to open a pty.  */
 #define PTY_ITERATION