diff options
Diffstat (limited to 'semaphore.c')
| -rw-r--r-- | semaphore.c | 215 |
1 files changed, 98 insertions, 117 deletions
diff --git a/semaphore.c b/semaphore.c index 0d46614..cd463d3 100644 --- a/semaphore.c +++ b/semaphore.c @@ -9,17 +9,6 @@ * * POSIX 1003.1b-1993 (POSIX.1b) * - * They are supposed to follow the older UNIX convention for - * reporting errors. That is, on failure they are supposed - * to return a value of -1 and store the appropriate error - * number into 'errno'. - * HOWEVER,errno cannot be modified in a multithreaded - * program on WIN32; therefore, the value is returned as - * the function value. - * It is recommended that you compare for zero (0) for success - * instead of -1 for failure when checking the status of - * these functions. - * * Contents: * Public Methods Author * -------------- ------ @@ -53,15 +42,17 @@ * MA 02111-1307, USA */ +#include <windows.h> +#include <process.h> #include <sys/timeb.h> - #include <string.h> -#include <pthread.h> -#include "implement.h" +#include "pthread.h" +#include "semaphore.h" + int -_pthread_sem_init (_pthread_sem_t * sem, int pshared, unsigned int value) +sem_init (sem_t * sem, int pshared, unsigned int value) /* * ------------------------------------------------------ * DOCPUBLIC @@ -70,7 +61,7 @@ _pthread_sem_init (_pthread_sem_t * sem, int pshared, unsigned int value) * * PARAMETERS * sem - * pointer to an instance of _pthread_sem_t + * pointer to an instance of sem_t * * pshared * if zero, this semaphore may only be shared between @@ -87,6 +78,8 @@ _pthread_sem_init (_pthread_sem_t * sem, int pshared, unsigned int value) * * RESULTS * 0 successfully created semaphore, + * -1 failed, error in errno + * ERRNO * EINVAL 'sem' is not a valid semaphore, * ENOSPC a required resource has been exhausted, * ENOSYS semaphores are not supported, @@ -110,7 +103,7 @@ _pthread_sem_init (_pthread_sem_t * sem, int pshared, unsigned int value) { /* * NOTE: Taking advantage of the fact that - * _pthread_sem_t is a simple structure with one entry; + * sem_t is a simple structure with one entry; * We don't have to allocate it... */ *sem = CreateSemaphore ( @@ -125,13 +118,19 @@ _pthread_sem_init (_pthread_sem_t * sem, int pshared, unsigned int value) } } - return (result); + if (result != 0) + { + errno = result; + return -1; + } + + return 0; } /* sem_init */ int -_pthread_sem_destroy (_pthread_sem_t * sem) +sem_destroy (sem_t * sem) /* * ------------------------------------------------------ * DOCPUBLIC @@ -139,13 +138,15 @@ _pthread_sem_destroy (_pthread_sem_t * sem) * * PARAMETERS * sem - * pointer to an instance of _pthread_sem_t + * pointer to an instance of sem_t * * DESCRIPTION * This function destroys an unnamed semaphore. * * RESULTS * 0 successfully destroyed semaphore, + * -1 failed, error in errno + * ERRNO * EINVAL 'sem' is not a valid semaphore, * ENOSYS semaphores are not supported, * EBUSY threads (or processes) are currently @@ -154,17 +155,30 @@ _pthread_sem_destroy (_pthread_sem_t * sem) * ------------------------------------------------------ */ { - return ((sem == NULL) - ? EINVAL - : (CloseHandle (*sem) - ? 0 - : EINVAL)); + int result = 0; + + if (sem == NULL) + { + result = EINVAL; + } + else if (! CloseHandle (*sem)) + { + result = EINVAL; + } + + if (result != 0) + { + errno = result; + return -1; + } + + return 0; } /* sem_destroy */ int -_pthread_sem_trywait (_pthread_sem_t * sem) +sem_trywait (sem_t * sem) /* * ------------------------------------------------------ * DOCPUBLIC @@ -172,7 +186,7 @@ _pthread_sem_trywait (_pthread_sem_t * sem) * * PARAMETERS * sem - * pointer to an instance of _pthread_sem_t + * pointer to an instance of sem_t * * DESCRIPTION * This function tries to wait on a semaphore. If the @@ -182,6 +196,8 @@ _pthread_sem_trywait (_pthread_sem_t * sem) * * RESULTS * 0 successfully decreased semaphore, + * -1 failed, error in errno + * ERRNO * EAGAIN the semaphore was already locked, * EINVAL 'sem' is not a valid semaphore, * ENOSYS semaphores are not supported, @@ -191,67 +207,38 @@ _pthread_sem_trywait (_pthread_sem_t * sem) * ------------------------------------------------------ */ { - return ((sem == NULL) - ? EINVAL - : ((WaitForSingleObject (*sem, 0) == WAIT_TIMEOUT) - ? EAGAIN - : 0)); - -} /* sem_trywait */ + int result = 0; + if (sem == NULL) + { + result = EINVAL; + } + else if (WaitForSingleObject (*sem, 0) == WAIT_TIMEOUT) + { + result = EAGAIN; + } -int -_pthread_sem_wait (_pthread_sem_t * sem) - /* - * ------------------------------------------------------ - * DOCPUBLIC - * This function waits on a semaphore. - * - * PARAMETERS - * sem - * pointer to an instance of _pthread_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, - * 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. - * - * ------------------------------------------------------ - */ -{ + if (result != 0) + { + errno = result; + return -1; + } - return ((sem == NULL) - ? EINVAL - : pthreadCancelableWait (*sem) - ); + return 0; -} /* sem_wait */ +} /* sem_trywait */ int -_pthread_sem_timedwait (_pthread_sem_t * sem, const struct timespec * abstime) +sem_wait (sem_t * sem) /* * ------------------------------------------------------ * DOCPUBLIC - * This function waits on a semaphore possibly until - * 'abstime' time. + * This function waits on a semaphore. * * PARAMETERS * sem - * pointer to an instance of _pthread_sem_t - * - * abstime - * pointer to an instance of struct timespec + * pointer to an instance of sem_t * * DESCRIPTION * This function waits on a semaphore. If the @@ -261,64 +248,42 @@ _pthread_sem_timedwait (_pthread_sem_t * sem, const struct timespec * abstime) * 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. * * ------------------------------------------------------ */ { -#if defined(__MINGW32__) - struct timeb currSysTime; -#else - struct _timeb currSysTime; -#endif - const DWORD NANOSEC_PER_MILLISEC = 1000000; - const DWORD MILLISEC_PER_SEC = 1000; - DWORD milliseconds; + int result = 0; if (sem == NULL) { - return EINVAL; - } - - if (abstime == NULL) - { - milliseconds = INFINITE; + result = EINVAL; } else { - /* - * Calculate timeout as milliseconds from current system time. - */ - - /* get current system time */ - _ftime(&currSysTime); - - /* subtract current system time from abstime */ - milliseconds = (abstime->tv_sec - currSysTime.time) * MILLISEC_PER_SEC; - milliseconds += (abstime->tv_nsec / NANOSEC_PER_MILLISEC) - - currSysTime.millitm; + result = pthreadCancelableWait (*sem); + } - if (((int) milliseconds) < 0) - milliseconds = 0; + if (result != 0) + { + errno = result; + return -1; } - return (pthreadCancelableTimedWait (*sem, milliseconds)); + return 0; -} /* _pthread_sem_timedwait */ +} /* sem_wait */ int -_pthread_sem_post (_pthread_sem_t * sem) +sem_post (sem_t * sem) /* * ------------------------------------------------------ * DOCPUBLIC @@ -326,7 +291,7 @@ _pthread_sem_post (_pthread_sem_t * sem) * * PARAMETERS * sem - * pointer to an instance of _pthread_sem_t + * pointer to an instance of sem_t * * DESCRIPTION * This function posts a wakeup to a semaphore. If there @@ -334,17 +299,33 @@ _pthread_sem_post (_pthread_sem_t * sem) * otherwise, the semaphore value is incremented by one. * * RESULTS - * 0 successfully destroyed semaphore, + * 0 successfully posted semaphore, + * -1 failed, error in errno + * ERRNO * EINVAL 'sem' is not a valid semaphore, * ENOSYS semaphores are not supported, * * ------------------------------------------------------ */ { - return ((sem == NULL) - ? EINVAL - : (ReleaseSemaphore (*sem, 1, 0) - ? 0 - : EINVAL)); + int result = 0; + + if (sem == NULL) + { + result = EINVAL; + } + else if (! ReleaseSemaphore (*sem, 1, 0)) + { + result = EINVAL; + } + + + if (result != 0) + { + errno = result; + return -1; + } + + return 0; } /* sem_post */ |