Re: [ANNOUNCEMENT] cygwin 3.1.0-0.4 (TEST)

[Michael Haubenwallner <michael.haubenwallner@ssi-schaefer.com>]

On 9/5/19 3:16 PM, Ken Brown wrote:
> The following packages have been uploaded to the Cygwin distribution
> as test releases:
> 
> * cygwin-3.1.0-0.4
> * cygwin-devel-3.1.0-0.4
> * cygwin-doc-3.1.0-0.4

> - New APIs: sched_getaffinity, sched_setaffinity, pthread_getaffinity_np,
>   pthread_setaffinity_np, plus CPU_SET macros.

There's some problem with <sched.h>, seen with boost-1.71.0/bootstrap.sh,
even after tweaking their sysinfo.cpp like this to include <sched.h>:

-#if defined(OS_LINUX)
+#if defined(OS_LINUX) || defined(OS_CYGWIN)

This boils down to a test case like this that succeeds to *compile* on Linux,
although requires _GNU_SOURCE to be defined earlier to perform anything useful:

$ cat > test.cc <<'EOF'
#ifdef LIKE_BOOST
# include <pthread.h>
# define _GNU_SOURCE
#endif
#include <sched.h>
int main()
{
#if defined(CPU_COUNT_S)
  ::cpu_set_t cpu_set;
  if (::sched_getaffinity(0, sizeof(cpu_set_t), &cpu_set) == 0)
    {
      return CPU_COUNT_S(sizeof(cpu_set_t), &cpu_set);
    }
#endif
  return 0;
}
EOF

Both these commands fail to compile on Cygwin with identical error:
$ g++ test.c -DLIKE_BOOST
$ g++ test.c
test.c: In function ‘main’:
test.c:10:7: warning: implicit declaration of function ‘sched_getaffinity’; did you mean ‘sched_getparam’? [-Wimplicit-function-declaration]
   if (sched_getaffinity(0, sizeof(cpu_set_t), &cpu_set) == 0)
       ^~~~~~~~~~~~~~~~~
       sched_getparam

Actually it is boost's fault to include <pthread.h> before defining _GNU_SOURCE,
but it feels like Cygwin should *not* define CPU_COUNT_S without _GNU_SOURCE.

Thoughts?
/haubi/

PS: This does work as expected:
$ g++ test.c -D_GNU_SOURCE

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