fileno() was failing when passed a NULL. I'm guessing that we don't really need to increase the refcount on a NULL fd.

1 files changed, 3 insertions, 1 deletions

diff --git a/perlio.c b/perlio.c
index b935734e4c..0a086a8b4f 100644
--- a/perlio.c
+++ b/perlio.c
@@ -3033,7 +3033,9 @@ PerlIOStdio_dup(pTHX_ PerlIO *f, PerlIO *o, CLONE_PARAMS *param, int flags)
     	stdio = PerlSIO_fdopen(fd, PerlIO_modestr(o,mode));
     set_this:
 	PerlIOSelf(f, PerlIOStdio)->stdio = stdio;
-	PerlIOUnix_refcnt_inc(fileno(stdio));
+        if(stdio) {
+	    PerlIOUnix_refcnt_inc(fileno(stdio));
+        }
     }
     return f;
 }