NAME

pause - suspend the thread until a signal is received

SYNOPSIS

#include <unistd.h>

int pause(void);


DESCRIPTION

The pause() function shall suspend the calling thread until delivery of a signal whose action is either to execute a signal-catching function or to terminate the process.

If the action is to terminate the process, pause() shall not return.

If the action is to execute a signal-catching function, pause() shall return after the signal-catching function returns.

RETURN VALUE

Since pause() suspends thread execution indefinitely unless interrupted by a signal, there is no successful completion return value. A value of -1 shall be returned and errno set to indicate the error.

ERRORS

The pause() function shall fail if:

[EINTR]

A signal is caught by the calling process and control is returned from the signal-catching function.

EXAMPLES

None.

APPLICATION USAGE

Many common uses of pause() have timing windows. The scenario involves checking a condition related to a signal and, if the signal has not occurred, calling pause(). When the signal occurs between the check and the call to pause(), the process often blocks indefinitely. The sigprocmask() and sigsuspend() functions can be used to avoid this type of problem.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

sigsuspend(), the Base Definitions volume of IEEE Std 1003.1-2001, <unistd.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 5

The DESCRIPTION is updated for alignment with the POSIX Threads Extension.

Issue 6

The APPLICATION USAGE section is added.