aboutsummaryrefslogtreecommitdiff
path: root/pthreads/sem_post_multiple.c
diff options
context:
space:
mode:
Diffstat (limited to 'pthreads/sem_post_multiple.c')
-rw-r--r--pthreads/sem_post_multiple.c142
1 files changed, 142 insertions, 0 deletions
diff --git a/pthreads/sem_post_multiple.c b/pthreads/sem_post_multiple.c
new file mode 100644
index 000000000..3d1e4ef28
--- /dev/null
+++ b/pthreads/sem_post_multiple.c
@@ -0,0 +1,142 @@
+/*
+ * -------------------------------------------------------------
+ *
+ * Module: sem_post_multiple.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) 1999,2005 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
+ */
+
+#include "pthread.h"
+#include "semaphore.h"
+#include "implement.h"
+
+
+int
+sem_post_multiple (sem_t * sem, int count)
+ /*
+ * ------------------------------------------------------
+ * DOCPUBLIC
+ * This function posts multiple wakeups to a semaphore.
+ *
+ * PARAMETERS
+ * sem
+ * pointer to an instance of sem_t
+ *
+ * count
+ * counter, must be greater than zero.
+ *
+ * DESCRIPTION
+ * This function posts multiple wakeups to a semaphore. If there
+ * are waiting threads (or processes), n <= count are awakened;
+ * the semaphore value is incremented by count - n.
+ *
+ * RESULTS
+ * 0 successfully posted semaphore,
+ * -1 failed, error in errno
+ * ERRNO
+ * EINVAL 'sem' is not a valid semaphore
+ * or count is less than or equal to zero.
+ * ERANGE semaphore count is too big
+ *
+ * ------------------------------------------------------
+ */
+{
+ int result = 0;
+ long waiters;
+ sem_t s = *sem;
+
+ if (s == NULL || count <= 0)
+ {
+ result = EINVAL;
+ }
+ else if ((result = pthread_mutex_lock (&s->lock)) == 0)
+ {
+ /* See sem_destroy.c
+ */
+ if (*sem == NULL)
+ {
+ (void) pthread_mutex_unlock (&s->lock);
+ result = EINVAL;
+ return -1;
+ }
+
+ if (s->value <= (SEM_VALUE_MAX - count))
+ {
+ waiters = -s->value;
+ s->value += count;
+ if (waiters > 0)
+ {
+#ifdef NEED_SEM
+ if (SetEvent(s->sem))
+ {
+ waiters--;
+ s->leftToUnblock += count - 1;
+ if (s->leftToUnblock > waiters)
+ {
+ s->leftToUnblock = waiters;
+ }
+ }
+#else
+ if (ReleaseSemaphore (s->sem, (waiters<=count)?waiters:count, 0))
+ {
+ /* No action */
+ }
+#endif
+ else
+ {
+ s->value -= count;
+ result = EINVAL;
+ }
+ }
+ }
+ else
+ {
+ result = ERANGE;
+ }
+ (void) pthread_mutex_unlock (&s->lock);
+ }
+
+ if (result != 0)
+ {
+ errno = result;
+ return -1;
+ }
+
+ return 0;
+
+} /* sem_post_multiple */