maint/gnulib/lib/glthread/threadlib.c

/* */
This source file includes following definitions.
glthread_in_use
dummy_thread_func
glthread_in_use
   1 /* Multithreading primitives.
   2    Copyright (C) 2005-2021 Free Software Foundation, Inc.
   3 
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8 
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13 
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16 
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2005.  */
  18 
  19 #include <config.h>
  20 
  21 /* ========================================================================= */
  22 
  23 #if USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS
  24 
  25 /* Use the POSIX threads library.  */
  26 
  27 # include <errno.h>
  28 # include <pthread.h>
  29 # include <stdlib.h>
  30 
  31 # if PTHREAD_IN_USE_DETECTION_HARD
  32 
  33 #  if defined __FreeBSD__ || defined __DragonFly__                 /* FreeBSD */
  34 
  35 /* Test using pthread_key_create.  */
  36 
  37 int
  38 glthread_in_use (void)
     /*  */
  39 {
  40   static int tested;
  41   static int result; /* 1: linked with -lpthread, 0: only with libc */
  42 
  43   if (!tested)
  44     {
  45       pthread_key_t key;
  46       int err = pthread_key_create (&key, NULL);
  47 
  48       if (err == ENOSYS)
  49         result = 0;
  50       else
  51         {
  52           result = 1;
  53           if (err == 0)
  54             pthread_key_delete (key);
  55         }
  56       tested = 1;
  57     }
  58   return result;
  59 }
  60 
  61 #  else                                                     /* Solaris, HP-UX */
  62 
  63 /* Test using pthread_create.  */
  64 
  65 /* The function to be executed by a dummy thread.  */
  66 static void *
  67 dummy_thread_func (void *arg)
     /*  */
  68 {
  69   return arg;
  70 }
  71 
  72 int
  73 glthread_in_use (void)
     /*  */
  74 {
  75   static int tested;
  76   static int result; /* 1: linked with -lpthread, 0: only with libc */
  77 
  78   if (!tested)
  79     {
  80       pthread_t thread;
  81 
  82       if (pthread_create (&thread, NULL, dummy_thread_func, NULL) != 0)
  83         /* Thread creation failed.  */
  84         result = 0;
  85       else
  86         {
  87           /* Thread creation works.  */
  88           void *retval;
  89           if (pthread_join (thread, &retval) != 0)
  90             abort ();
  91           result = 1;
  92         }
  93       tested = 1;
  94     }
  95   return result;
  96 }
  97 
  98 #  endif
  99 
 100 # endif
 101 
 102 #endif
 103 
 104 /* ========================================================================= */
 105 
 106 /* This declaration is solely to ensure that after preprocessing
 107    this file is never empty.  */
 108 typedef int dummy;
/* */
root/maint/gnulib/lib/glthread/threadlib.c

DEFINITIONS
