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NAME

thr_suspend, thr_continue - suspend or continue thread execution
 

SYNOPSIS

cc -mt [ flag... ] file...[ library... ]
#include <thread.h> 

int thr_suspend(thread_t target_thread);

int thr_continue(thread_t target_thread);

DESCRIPTION

The thr_suspend() function immediately suspends the execution of the thread specified by target_thread. On successful return from thr_suspend(), the suspended thread is no longer executing. Once a thread is suspended, subsequent calls to thr_suspend() have no effect.

The thr_continue() function resumes the execution of a suspended thread. Once a suspended thread is continued, subsequent calls to thr_continue() have no effect.

A suspended thread will not be awakened by any mechanism other than a call to thr_continue(). Signals and the effect of calls tomutex_unlock(3C), rw_unlock(3C), sema_post(3C), cond_signal(3C), and cond_broadcast(3C) remain pending until the execution of the thread is resumed by thr_continue().  

RETURN VALUES

If successful, the thr_suspend() and thr_continue() functions return 0. Otherwise, a non-zero value is returned to indicate the error.  

ERRORS

The thr_suspend() and thr_continue() functions will fail if:

ESRCH

The target_thread cannot be found in the current process.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE MT-Level MT-Safe

SEE ALSO

thr_create(3C), thr_join(3C), attributes(5), standards(5)  

WARNINGS

The thr_suspend() function is extremely difficult to use safely because it suspends the target thread with no concern for the target thread's state. The target thread could be holding locks, waiting for a lock, or waiting on a condition variable when it is unconditionally suspended. The thread will not run until thr_continue() is applied, regardless of any calls to mutex_unlock(), cond_signal(), or cond_broadcast() by other threads. Its existence on a sleep queue can interfere with the waking up of other threads that are on the same sleep queue.

The thr_suspend() and thr_continue() functions should be avoided. Mechanisms that involve the cooperation of the targeted thread, such as mutex locks and condition variables, should be employed instead.

Index

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUES

ERRORS

ATTRIBUTES

SEE ALSO

WARNINGS

Партнёры:

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