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Diffstat (limited to 'sem_timedwait.c')
| -rw-r--r-- | sem_timedwait.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/sem_timedwait.c b/sem_timedwait.c new file mode 100644 index 0000000..11178f2 --- /dev/null +++ b/sem_timedwait.c @@ -0,0 +1,198 @@ +/* + * ------------------------------------------------------------- + * + * Module: sem_timedwait.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 + */ + +#ifndef _UWIN +#include <process.h> +#endif +#ifndef NEED_FTIME +#include <sys/timeb.h> +#endif + +#include "pthread.h" +#include "semaphore.h" +#include "implement.h" + + +int +sem_timedwait (sem_t * sem, const struct timespec * abstime) + /* + * ------------------------------------------------------ + * DOCPUBLIC + * This function waits on a semaphore possibly until + * 'abstime' time. + * + * PARAMETERS + * sem + * pointer to an instance of sem_t + * + * abstime + * pointer to an instance of struct timespec + * + * 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. + * + * If 'abstime' is a NULL pointer then this function will + * block 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. + * ETIMEDOUT abstime elapsed before success. + * + * ------------------------------------------------------ + */ +{ + int result = 0; + +#ifdef NEED_FTIME + + struct timespec currSysTime; + +#else /* NEED_FTIME */ + + struct _timeb currSysTime; + +#endif /* NEED_FTIME */ + + const DWORD NANOSEC_PER_MILLISEC = 1000000; + const DWORD MILLISEC_PER_SEC = 1000; + DWORD milliseconds; + + if (sem == NULL) + { + result = EINVAL; + } + else + { + if (abstime == NULL) + { + milliseconds = INFINITE; + } + else + { + /* + * Calculate timeout as milliseconds from current system time. + */ + + /* get current system time */ + +#ifdef NEED_FTIME + + { + FILETIME ft; + SYSTEMTIME st; + + GetSystemTime(&st); + SystemTimeToFileTime(&st, &ft); + /* + * GetSystemTimeAsFileTime(&ft); would be faster, + * but it does not exist on WinCE + */ + + ptw32_filetime_to_timespec(&ft, &currSysTime); + } + + /* + * subtract current system time from abstime + */ + milliseconds = (abstime->tv_sec - currSysTime.tv_sec) * MILLISEC_PER_SEC; + milliseconds += ((abstime->tv_nsec - currSysTime.tv_nsec) + + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC; + +#else /* NEED_FTIME */ + _ftime(&currSysTime); + + /* + * subtract current system time from abstime + */ + milliseconds = (abstime->tv_sec - currSysTime.time) * MILLISEC_PER_SEC; + milliseconds += ((abstime->tv_nsec + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC) + - currSysTime.millitm; + +#endif /* NEED_FTIME */ + + + if (((int) milliseconds) < 0) + milliseconds = 0; + } + +#ifdef NEED_SEM + + result = (pthreadCancelableTimedWait ((*sem)->event, milliseconds)); + +#else /* NEED_SEM */ + + result = (pthreadCancelableTimedWait ((*sem)->sem, milliseconds)); + +#endif + + } + + if (result != 0) + { + + errno = result; + return -1; + + } + +#ifdef NEED_SEM + + ptw32_decrease_semaphore(sem); + +#endif /* NEED_SEM */ + + return 0; + +} /* sem_timedwait */ |