POSIX Threads for Windows Code

/*
 * sched_getscheduler.c
 * 
 * Description:
 * POSIX thread functions that deal with thread scheduling.
 *
 * --------------------------------------------------------------------------
 *
 *      Pthreads4w - POSIX Threads for Windows
 *      Copyright 1998 John E. Bossom
 *      Copyright 1999-2018, Pthreads4w contributors
 *
 *      Homepage: https://sourceforge.net/projects/pthreads4w/
 *
 *      The current list of contributors is contained
 *      in the file CONTRIBUTORS included with the source
 *      code distribution. The list can also be seen at the
 *      following World Wide Web location:
 *
 *      https://sourceforge.net/p/pthreads4w/wiki/Contributors/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "pthread.h"
#include "implement.h"
#include "sched.h"

int
sched_getscheduler (pid_t pid)
{
  /*
   * Win32 only has one policy which we call SCHED_OTHER.
   * However, we try to provide other valid side-effects
   * such as EPERM and ESRCH errors.
   */
  if (0 != pid)
    {
      int selfPid = (int) GetCurrentProcessId ();

      if (pid != selfPid)
	{
	  HANDLE h =
	    OpenProcess (PROCESS_QUERY_INFORMATION,  __PTW32_FALSE, (DWORD) pid);

	  if (NULL == h)
	    {
		   __PTW32_SET_ERRNO(((0xFF & ERROR_ACCESS_DENIED) == GetLastError()) ? EPERM : ESRCH);
	      return -1;
	    }
	  else
	    CloseHandle(h);
	}
    }

  return SCHED_OTHER;
}