diff --git a/scsh/sighandlers1.c b/scsh/sighandlers1.c
index 0216bf9..5a6a245 100644
--- a/scsh/sighandlers1.c
+++ b/scsh/sighandlers1.c
@@ -175,7 +175,7 @@ void install_scsh_handlers(void)
   new.sa_flags = 0;
 
   for(i=max_sig; i>=0; i--)
-    if( sig2int[i] ) {
+    if( sig2int[i] >= 0 ) {
       /* This is a signal we want the S48 interrupt system to handle. */
       sigaction(i, &new, 0);
       }