Make the four-argument form of select() return undef

instead of -1 on error.

p4raw-id: //depot/perl@24223

1 files changed, 4 insertions, 1 deletions

diff --git a/pp_sys.c b/pp_sys.c
index 4b7944a4df..16f539b79e 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -1129,7 +1129,10 @@ PP(pp_sselect)
 	}
     }
 
-    PUSHi(nfound);
+    if (nfound == -1)
+	PUSHs(&PL_sv_undef);
+    else
+	PUSHi(nfound);
     if (GIMME == G_ARRAY && tbuf) {
 	value = (NV)(timebuf.tv_sec) +
 		(NV)(timebuf.tv_usec) / 1000000.0;