PAUSE(3P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

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.

The following sections are informative.

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>

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .