On Tue, Aug 16, 2016 at 6:17 PM, Hanno Böck <ha...@hboeck.de> wrote: > Hi, > > The variable presume_output_tty is defined both in the diff.h header > and the file util.c (which includes diff.h). > > The diff.h file makes sure that the variable is declared as external > except when it's included by the main program diff.c. But as it's also > declared in util.c we end up having two non-external declarations of it. > > Traditionally gcc has allowed this behavior, which is probably the > reason it has not been spottet before, but it's not correct C. One can > get a more strict behavior here by passing -fno-common to the CFLAGS and > LDFLAGS and then linking will fail. > > The solution is simple: Remove the superfluous declaration in util.c, > see attached patch. Please apply.
Good catch. Thank you! I will look into adding -fno-common when it is accepted. Here's the patch I expect to push soon:
From c2dc91f1968c6ccd8ba623f9fa391f529ab800ab Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Hanno=20B=C3=B6ck?= <ha...@hboeck.de> Date: Tue, 16 Aug 2016 22:02:13 -0700 Subject: [PATCH] diff: avoid duplicate definition of presume_output_tty * src/util.c (presume_output_tty): Remove this definition. The other is in diff.h. Reported in https://bugs.gnu.org/24248 --- src/util.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/src/util.c b/src/util.c index d7b8925..76872cb 100644 --- a/src/util.c +++ b/src/util.c @@ -44,8 +44,6 @@ char const pr_program[] = PR_PROGRAM; -bool presume_output_tty; - /* Queue up one-line messages to be printed at the end, when -l is specified. Each message is recorded with a 'struct msg'. */ -- 2.8.0-rc2
