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1 /*
2  * tryentercs.c
3  *
4  *
5  * --------------------------------------------------------------------------
6  *
7  *      Pthreads-win32 - POSIX Threads Library for Win32
8  *      Copyright(C) 1998 John E. Bossom
9  *      Copyright(C) 1999,2005 Pthreads-win32 contributors
10  *
11  *      Contact Email: rpj@callisto.canberra.edu.au
12  *
13  *      The current list of contributors is contained
14  *      in the file CONTRIBUTORS included with the source
15  *      code distribution. The list can also be seen at the
16  *      following World Wide Web location:
17  *      http://sources.redhat.com/pthreads-win32/contributors.html
18  *
19  *      This library is free software; you can redistribute it and/or
20  *      modify it under the terms of the GNU Lesser General Public
21  *      License as published by the Free Software Foundation; either
22  *      version 2 of the License, or (at your option) any later version.
23  *
24  *      This library is distributed in the hope that it will be useful,
25  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
26  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
27  *      Lesser General Public License for more details.
28  *
29  *      You should have received a copy of the GNU Lesser General Public
30  *      License along with this library in the file COPYING.LIB;
31  *      if not, write to the Free Software Foundation, Inc.,
32  *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
33  *
34  * --------------------------------------------------------------------------
35  *
36  * See if we have the TryEnterCriticalSection function.
37  * Does not use any part of pthreads.
38  */
39 
40 #include <windows.h>
41 #include <process.h>
42 #include <stdio.h>
43 
44 /*
45  * Function pointer to TryEnterCriticalSection if it exists
46  * - otherwise NULL
47  */
48 BOOL (WINAPI *_try_enter_critical_section)(LPCRITICAL_SECTION) =
49 NULL;
50 
51 /*
52  * Handle to kernel32.dll
53  */
54 static HINSTANCE _h_kernel32;
55 
56 
57 int
main()58 main()
59 {
60   CRITICAL_SECTION cs;
61 
62   SetLastError(0);
63 
64   printf("Last Error [main enter] %ld\n", (long) GetLastError());
65 
66   /*
67    * Load KERNEL32 and try to get address of TryEnterCriticalSection
68    */
69   _h_kernel32 = LoadLibrary(TEXT("KERNEL32.DLL"));
70   _try_enter_critical_section =
71         (BOOL (WINAPI *)(LPCRITICAL_SECTION))
72         GetProcAddress(_h_kernel32,
73                          (LPCSTR) "TryEnterCriticalSection");
74 
75   if (_try_enter_critical_section != NULL)
76     {
77       InitializeCriticalSection(&cs);
78 
79       SetLastError(0);
80 
81       if ((*_try_enter_critical_section)(&cs) != 0)
82         {
83           LeaveCriticalSection(&cs);
84         }
85 	else
86 	  {
87 	    printf("Last Error [try enter] %ld\n", (long) GetLastError());
88 
89 	    _try_enter_critical_section = NULL;
90 	  }
91       DeleteCriticalSection(&cs);
92     }
93 
94   (void) FreeLibrary(_h_kernel32);
95 
96   printf("This system %s TryEnterCriticalSection.\n",
97          (_try_enter_critical_section == NULL) ? "DOES NOT SUPPORT" : "SUPPORTS");
98   printf("POSIX Mutexes will be based on Win32 %s.\n",
99          (_try_enter_critical_section == NULL) ? "Mutexes" : "Critical Sections");
100 
101   return(0);
102 }
103 
104