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pthread_cond_sig_preempt_int_np(3) [osf1 man page]

pthread_cond_sig_preempt_int_np(3)			     Library Functions Manual				pthread_cond_sig_preempt_int_np(3)

NAME
pthread_cond_sig_preempt_int_np - Wakes one thread that is waiting on the specified condition variable (called from interrupt level only). LIBRARY
DECthreads POSIX 1003.1c Library (libpthread.so) SYNOPSIS
#include <pthread.h> int pthread_cond_sig_preempt_int_np( pthread_cond_t *cond); STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: IEEE Std 1003.1c-1995, POSIX System Application Program Interface PARAMETERS
Condition variable to be signaled. DESCRIPTION
This routine wakes one thread waiting on a condition variable. It can only be called from a software interrupt handler routine. Calling this routine implies that it might be possible for a single waiting thread to proceed. Call this routine when any thread waiting on the specified condition variable might find its predicate true. The scheduling policies of the waiting threads determine which thread is awakened. For policies SCHED_FIFO and SCHED_RR, a blocked thread is chosen in priority order, using first-in/first-out (FIFO) within priorities. You can call this routine when the associated mutex is either locked or unlocked. Never try to lock a mutex from an interrupt handler. This routine allows you to signal a thread from a software interrupt handler. Do not call this routine from noninterrupt code. If you want to signal a thread from the normal interrupt level, use pthread_cond_signal(3). NOTE: If a waiting thread has a preemptive scheduling policy and a higher priority than the thread which was running when the interrupt occurred, then the waiting thread will preempt the interrupt routine and begin to run immediately. This is unlike pthread_cond_sig- nal_int_np(3) which causes the condition variable to be signaled at a safe point after the interrupt has completed. pthread_cond_sig_pre- empt_int_np(3) avoids the possible latency which pthread_cond_signal_int_np(3) may introduce; however, a side effect of this is that during the call to pthread_cond_sig_preempt_int_np(3) other threads may run if a preemption occurs; thus, once an interrupt routine calls pthread_cond_sig_preempt_int_np(3) it can no longer rely on any assumptions of exclusivity or atomicity which are typically provided by interrupt routines. Furthermore, once the call to pthread_cond_sig_preempt_int_np(3) is made, in addition to other threads running, subse- quent interrupts may be delivered at any time as well (that is, they will not be blocked until the current interrupt completes). For this reason, it is recommended that pthread_cond_sig_preempt_int_np(3) be called as the last statement in the interrupt routine. RETURN VALUES
If an error condition occurs, this routine returns an integer value indicating the type of error. Possible return values are as follows: Successful completion. The value specified by cond is not a valid condition variable. ERRORS
None RELATED INFORMATION
Functions: pthread_cond_broadcast(3), pthread_cond_signal(3), pthread_cond_signal_int_np(3), pthread_cond_timedwait(3), pthread_cond_wait(3) Manuals: Guide to DECthreads and Programmer's Guide delim off pthread_cond_sig_preempt_int_np(3)

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pthread_cond_broadcast(3)				     Library Functions Manual					 pthread_cond_broadcast(3)

NAME
pthread_cond_broadcast - Wakes all threads that are waiting on the specified condition variable. LIBRARY
DECthreads POSIX 1003.1c Library (libpthread.so) SYNOPSIS
#include <pthread.h> int pthread_cond_broadcast( pthread_cond_t *cond); STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: IEEE Std 1003.1c-1995, POSIX System Application Program Interface PARAMETERS
Condition variable upon which the threads (to be awakened) are waiting. DESCRIPTION
This routine unblocks all threads waiting on the specified condition variable cond. Calling this routine implies that data guarded by the associated mutex has changed, so that it might be possible for one or more waiting threads to proceed. The threads that are unblocked shall contend for the mutex according to their respective scheduling policies (if applicable). If only one of the threads waiting on a condition variable may be able to proceed, but any single thread can proceed, then use pthread_cond_signal(3) instead. Whether the associated mutex is locked or unlocked, you can still call this routine. However, if predictable scheduling behavior is required, that mutex should then be locked by the thread calling the pthread_cond_broadcast(3) routine. If no threads are waiting on the specified condition variable, this routine takes no action. The broadcast does not propagate to the next condition variable wait. RETURN VALUES
If an error condition occurs, this routine returns an integer value indicating the type of error. Possible return values are as follows: Successful completion. The value specified by cond is invalid. ERRORS
None RELATED INFORMATION
Functions: pthread_cond_destroy(3), pthread_cond_init(3), pthread_cond_signal(3), pthread_cond_timedwait(3), pthread_cond_wait(3) Manuals: Guide to DECthreads and Programmer's Guide delim off pthread_cond_broadcast(3)
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