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.
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.
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.
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