1 /*
2 * errno.c
3 *
4 * Description:
5 * This translation unit implements routines associated with spawning a new
6 * thread.
7 *
8 * --------------------------------------------------------------------------
9 *
10 * Pthreads-win32 - POSIX Threads Library for Win32
11 * Copyright(C) 1998 John E. Bossom
12 * Copyright(C) 1999,2005 Pthreads-win32 contributors
13 *
14 * Contact Email: rpj@callisto.canberra.edu.au
15 *
16 * The current list of contributors is contained
17 * in the file CONTRIBUTORS included with the source
18 * code distribution. The list can also be seen at the
19 * following World Wide Web location:
20 * http://sources.redhat.com/pthreads-win32/contributors.html
21 *
22 * This library is free software; you can redistribute it and/or
23 * modify it under the terms of the GNU Lesser General Public
24 * License as published by the Free Software Foundation; either
25 * version 2 of the License, or (at your option) any later version.
26 *
27 * This library is distributed in the hope that it will be useful,
28 * but WITHOUT ANY WARRANTY; without even the implied warranty of
29 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
30 * Lesser General Public License for more details.
31 *
32 * You should have received a copy of the GNU Lesser General Public
33 * License along with this library in the file COPYING.LIB;
34 * if not, write to the Free Software Foundation, Inc.,
35 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
36 */
37
38 #if defined(NEED_ERRNO)
39
40 #include "pthread.h"
41 #include "implement.h"
42
43 static int reallyBad = ENOMEM;
44
45 /*
46 * Re-entrant errno.
47 *
48 * Each thread has it's own errno variable in pthread_t.
49 *
50 * The benefit of using the pthread_t structure
51 * instead of another TSD key is TSD keys are limited
52 * on Win32 to 64 per process. Secondly, to implement
53 * it properly without using pthread_t you'd need
54 * to dynamically allocate an int on starting the thread
55 * and store it manually into TLS and then ensure that you free
56 * it on thread termination. We get all that for free
57 * by simply storing the errno on the pthread_t structure.
58 *
59 * MSVC and Mingw32 already have their own thread-safe errno.
60 *
61 * #if defined( _REENTRANT ) || defined( _MT )
62 * #define errno *_errno()
63 *
64 * int *_errno( void );
65 * #else
66 * extern int errno;
67 * #endif
68 *
69 */
70
71 int *
_errno(void)72 _errno (void)
73 {
74 pthread_t self;
75 int *result;
76
77 if ((self = pthread_self ()).p == NULL)
78 {
79 /*
80 * Yikes! unable to allocate a thread!
81 * Throw an exception? return an error?
82 */
83 result = &reallyBad;
84 }
85 else
86 {
87 result = (int *)(&self.p->exitStatus);
88 }
89
90 return (result);
91
92 } /* _errno */
93
94 #endif /* (NEED_ERRNO) */
95