RE: [PATCH v2 1/7] common: add scoped_fd

["Metzger, Markus T" <markus.t.metzger@intel.com>]

Hello Yao,

> There is no such error with i686-w64-mingw32-g++ 5.3.1.  Can we use "open"
> instead?

A fixed filename works most of the time but I'd rather use a temporary file if possible.


> > +/* Test that the file descriptor is closed.  */ static void
> > +test_destroy () {
> > +  char filename[] = "scoped_fd-selftest-XXXXXX";
> > +  int fd = mkstemp (filename);
> > +  SELF_CHECK (fd >= 0);
> 
> Hi Markus,
> I failed to build this file with i686-w64-mingw32-g++ 4.8.2, shipped in Ubuntu
> 14.04.
> 
> gdb/unittests/scoped_fd-selftests.c:37:29: error: ‘mkstemp’ was not declared in
> this scope
>    int fd = mkstemp (filename);
>                              ^

This is supposed to be a glibc function.  But it is guarded by some feature macros.
Quote from mkstemp(3): "

       mkstemp():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
           || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200112L

       mkostemp(): _GNU_SOURCE
       mkstemps(): _BSD_SOURCE || _SVID_SOURCE
       mkostemps(): _GNU_SOURCE
"

Maybe the newer compiler is setting some macros automatically that the older compiler doesn't set.
Could you try setting, say, _POSIX_C_SOURCE or try using mkostemp() instead of mkstemp()?

If that doesn't help, I'll try to find a Ubuntu 14.04 to reproduce the issue.

thanks,
Markus.

> -----Original Message-----
> From: Yao Qi [mailto:qiyaoltc@gmail.com]
> Sent: 13 February 2018 17:48
> To: Metzger, Markus T <markus.t.metzger@intel.com>
> Cc: GDB Patches <gdb-patches@sourceware.org>
> Subject: Re: [PATCH v2 1/7] common: add scoped_fd
> 
> On Fri, Jan 26, 2018 at 2:14 PM, Markus Metzger <markus.t.metzger@intel.com>
> wrote:
> > +
> > +/* Test that the file descriptor is closed.  */ static void
> > +test_destroy () {
> > +  char filename[] = "scoped_fd-selftest-XXXXXX";
> > +  int fd = mkstemp (filename);
> > +  SELF_CHECK (fd >= 0);
> 
> Hi Markus,
> I failed to build this file with i686-w64-mingw32-g++ 4.8.2, shipped in Ubuntu
> 14.04.
> 
> gdb/unittests/scoped_fd-selftests.c:37:29: error: ‘mkstemp’ was not declared in
> this scope
>    int fd = mkstemp (filename);
>                              ^
> gdb/unittests/scoped_fd-selftests.c: In function ‘void
> selftests::scoped_fd::test_release()’:
> gdb/unittests/scoped_fd-selftests.c:56:29: error: ‘mkstemp’ was not declared in
> this scope
>    int fd = mkstemp (filename);
>                              ^
> 
> There is no such error with i686-w64-mingw32-g++ 5.3.1.  Can we use "open"
> instead?
> 
> --
> Yao (齐尧)
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