From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: Patrick Chkoreff <pc@fexl.com>
Cc: cygwin@cygwin.com
Subject: Re: setrlimit always fails
Date: Mon, 15 Feb 2021 21:48:04 +0100 [thread overview]
Message-ID: <YCreBGKMpVwfWrvR@calimero.vinschen.de> (raw)
In-Reply-To: <b55c516e-4b20-2dbb-3785-a7006dd049eb@fexl.com>
On Feb 15 14:54, Patrick Chkoreff wrote:
> Corinna Vinschen wrote on 2/15/21 4:14 AM:
>
> > That looks wrong. The __USE_<standard> flags are internal flags from
> > GLibc and not supposed to be used by application code. Check the Linux
> > man page for strptime, the usage of _XOPEN_SOURCE or another flag
> > including _XOPEN_SOURCE (e. g. _GNU_SOURCE) is required. So this:
> >
> > #define _XOPEN_SOURCE
> > #include <time.h>
>
> One would think so, but I tried it on two different Linux machines and
> it failed with:
>
> error: ‘strptime’ undeclared
>
> To fix that, I must define _USE_XOPEN
You really, really must not use this macro.
> #else
>
> #include <stdint.h>
> #include <sys/time.h>
> #define __USE_XOPEN
> #include <time.h>
>
> #endif
>
> void stuff(void)
> {
> uint64_t n;
> time_t t;
> struct timeval tv;
> (void)n;
> (void)t;
> (void)tv;
> (void)time;
> (void)gettimeofday;
> (void)timegm;
> (void)timelocal;
> (void)gmtime;
> (void)localtime;
> (void)strftime;
> (void)strptime;
> }
The problem here is that you mix functions only defined under
_XOPEN_SOURCE with stuff only defined with _DEFAULT_SOURCE from the same
header. Either define both feature test macros, or define _GNU_SOURCE.
This works:
#define _XOPEN_SOURCE
#define _DEFAULT_SOURCE
#include <stdint.h>
#include <sys/time.h>
#include <time.h>
void stuff(void)
[...]
This works, too:
#define _GNU_SOURCE
#include <stdint.h>
#include <sys/time.h>
#include <time.h>
void stuff(void)
[...]
Corinna
next prev parent reply other threads:[~2021-02-15 20:48 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 15:23 Patrick Chkoreff
2021-02-12 2:06 ` Ken Brown
2021-02-12 7:26 ` Brian Inglis
2021-02-12 9:12 ` Corinna Vinschen
2021-02-12 18:56 ` Brian Inglis
2021-02-12 20:38 ` Brian Inglis
2021-02-12 15:11 ` Patrick Chkoreff
2021-02-15 9:14 ` Corinna Vinschen
2021-02-15 19:54 ` Patrick Chkoreff
2021-02-15 20:48 ` Corinna Vinschen [this message]
2021-02-16 14:53 ` Patrick Chkoreff
2021-02-16 15:22 ` Marco Atzeri
2021-02-16 18:33 ` Brian Inglis
2021-02-12 9:11 ` Corinna Vinschen
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