NAME

thr_suspend —

suspend the calling thread

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <sys/thr.h>

int
thr_suspend(struct timespec *timeout);

DESCRIPTION

This function is intended for implementing threading. Normal applications should use pthread_cond_timedwait(3) together with pthread_cond_broadcast(3) for typical safe suspension with cooperation of the thread being suspended, or pthread_suspend_np(3) and pthread_resume_np(3) in some specific situations, instead.

The thr_suspend() system call puts the calling thread in a suspended state, where it is not eligible for CPU time. This state is exited by another thread calling thr_wake(2), when the time interval specified by timeout has elapsed, or by the delivery of a signal to the suspended thread.

If the timeout argument is NULL, the suspended state can be only terminated by explicit thr_wake() or signal.

If a wake from thr_wake(2) was delivered before the thr_suspend call, the thread is not put into a suspended state. Instead, the call returns immediately without an error.

If a thread previously called thr_wake(2) with its own thread identifier, which resulted in setting the internal kernel flag to immediately abort interruptible sleeps with an EINTR error (see thr_wake(2)), the flag is cleared. As with thr_wake(2) called from another thread, the next thr_suspend call does not result in suspension.

RETURN VALUES

The thr_suspend() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

ERRORS

The thr_suspend() operation returns the following errors:

[EFAULT]: The memory pointed to by the timeout argument is not valid.
[ETIMEDOUT]: The specified timeout expired.
[ETIMEDOUT]: The timeout argument specified a zero time interval.
[EINTR]: The sleep was interrupted by a signal.

STANDARDS

The thr_suspend() system call is non-standard.

HISTORY

The thr_suspend() system call first appeared in FreeBSD 5.2.