/* * ------------------------------------------------------------- * * 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) 1999,2003 Pthreads-win32 contributors * * Contact Email: rpj@callisto.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 { milliseconds = 0; /* * 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 in a way that checks * that abstime is never in the past, or is never equivalent to the * defined INFINITE value (0xFFFFFFFF). */ if (abstime->tv_sec >= currSysTime.tv_sec) { DWORD tmpMilliseconds; DWORD tmpCurrMilliseconds; tmpMilliseconds = (abstime->tv_sec - currSysTime.tv_sec) * MILLISEC_PER_SEC; tmpMilliseconds += ((abstime->tv_nsec + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC); tmpCurrMilliseconds = ((currSysTime.tv_nsec + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC); if (tmpMilliseconds > tmpCurrMilliseconds) { milliseconds = tmpMilliseconds - tmpCurrMilliseconds; if (milliseconds == INFINITE) { milliseconds--; } } } #else /* NEED_FTIME */ _ftime(&currSysTime); /* * subtract current system time from abstime in a way that checks * that abstime is never in the past, or is never equivalent to the * defined INFINITE value (0xFFFFFFFF). */ if (abstime->tv_sec >= currSysTime.time) { DWORD tmpMilliseconds; tmpMilliseconds = (abstime->tv_sec - currSysTime.time) * MILLISEC_PER_SEC; tmpMilliseconds += ((abstime->tv_nsec + (NANOSEC_PER_MILLISEC/2)) / NANOSEC_PER_MILLISEC); if (tmpMilliseconds > (DWORD) currSysTime.millitm) { milliseconds = tmpMilliseconds - currSysTime.millitm; if (milliseconds == INFINITE) { milliseconds--; } } } #endif /* NEED_FTIME */ } #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 */