diff options
author | rpj <rpj> | 2002-02-08 01:51:17 +0000 |
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committer | rpj <rpj> | 2002-02-08 01:51:17 +0000 |
commit | b29903300adc22ed277bbaa356aca8ed0c245957 (patch) | |
tree | 02921a99a145dda1e78a315cc75016443839f2e0 /semaphore_wait.c | |
parent | 14118935d2d6863a4746223d8e22c2e58ffebab5 (diff) |
Copyright notice updates; module splitting; POSIX version
conditional compilation; refinements; bug fixes. See the ChangeLog.
Diffstat (limited to 'semaphore_wait.c')
-rw-r--r-- | semaphore_wait.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/semaphore_wait.c b/semaphore_wait.c new file mode 100644 index 0000000..33bdb9c --- /dev/null +++ b/semaphore_wait.c @@ -0,0 +1,115 @@ +/* + * ------------------------------------------------------------- + * + * Module: semaphore_wait.c + * + * Purpose: + * Semaphores aren't actually part of the PThreads standard. + * They are defined by the POSIX Standard: + * + * POSIX 1003.1b-1993 (POSIX.1b) + * + * ------------------------------------------------------------- + * + * -------------------------------------------------------------------------- + * + * Pthreads-win32 - POSIX Threads Library for Win32 + * Copyright(C) 1998 John E. Bossom + * Copyright(C) 1999,2002 Pthreads-win32 contributors + * + * Contact Email: rpj@ise.canberra.edu.au + * + * 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: + * http://sources.redhat.com/pthreads-win32/contributors.html + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library in the file COPYING.LIB; + * if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +#include "pthread.h" +#include "semaphore.h" +#include "implement.h" + + +int +sem_wait (sem_t * sem) + /* + * ------------------------------------------------------ + * DOCPUBLIC + * This function waits on a semaphore. + * + * PARAMETERS + * sem + * pointer to an instance of sem_t + * + * DESCRIPTION + * This function waits on a semaphore. If the + * semaphore value is greater than zero, it decreases + * its value by one. If the semaphore value is zero, then + * the calling thread (or process) is blocked until it can + * successfully decrease the value or until interrupted by + * a signal. + * + * RESULTS + * 0 successfully decreased semaphore, + * -1 failed, error in errno + * ERRNO + * EINVAL 'sem' is not a valid semaphore, + * ENOSYS semaphores are not supported, + * EINTR the function was interrupted by a signal, + * EDEADLK a deadlock condition was detected. + * + * ------------------------------------------------------ + */ +{ + int result = 0; + + if (sem == NULL || *sem == NULL) + { + result = EINVAL; + } + else + { + +#ifdef NEED_SEM + + result = pthreadCancelableWait ((*sem)->event); + +#else /* NEED_SEM */ + + result = pthreadCancelableWait ((*sem)->sem); + +#endif /* NEED_SEM */ + + } + + if (result != 0) + { + errno = result; + return -1; + } + +#ifdef NEED_SEM + + ptw32_decrease_semaphore(sem); + +#endif /* NEED_SEM */ + + return 0; + +} /* sem_wait */ |