fix getc() to return empty string instead of undef on eof, as it was

documented to behave; still returns undef on error

p4raw-id: //depot/perl@1327

1 files changed, 11 insertions, 2 deletions

diff --git a/pp_sys.c b/pp_sys.c
index 6fb7cb5f18..44e520be20 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -889,6 +889,7 @@ PP(pp_getc)
     djSP; dTARGET;
     GV *gv;
     MAGIC *mg;
+    PerlIO *fp;
 
     if (MAXARG <= 0)
 	gv = stdingv;
@@ -910,11 +911,19 @@ PP(pp_getc)
 	    SvSetMagicSV_nosteal(TARG, TOPs);
 	RETURN;
     }
-    if (!gv || do_eof(gv)) /* make sure we have fp with something */
+    if (!gv || !GvIO(gv) || !(fp = IoIFP(GvIOp(gv))))	/* valid fp? */
 	RETPUSHUNDEF;
+
+    if (do_eof(gv)) {			/* handle magic argv, if needed */
+	if (PerlIO_error(fp))
+	    PUSHs(&sv_undef);
+	else
+	    PUSHp("",0);
+	RETURN;
+    }
     TAINT;
     sv_setpv(TARG, " ");
-    *SvPVX(TARG) = PerlIO_getc(IoIFP(GvIOp(gv))); /* should never be EOF */
+    *SvPVX(TARG) = PerlIO_getc(fp);	/* should never be EOF */
     PUSHTARG;
     RETURN;
 }