Don't use this function. Use sigsuspend(2) instead.
The function sigpause is designed to wait for some signal. It changes the
process' signal mask (set of blocked signals), and then waits for a signal to
arrive. Upon arrival of a signal, the original signal mask is restored.
The classical BSD version of this function appeared in 4.2BSD. It sets the
process' signal mask to sigmask. When the number of signals was
increased above 32, this version was replaced by the incompatible Unix95 one,
which removes only the specified signal sig from the process' signal
mask. The unfortunate situation with two incompatible functions with the same
name was solved by the sigsuspend(2) function, that takes a sigset_t
* parameter (instead of an int).
On Linux, this routine is a system call only on the Sparc (sparc64)
architecture. Libc4 and libc5 only know about the BSD version. Glibc uses the
BSD version unless _XOPEN_SOURCE is defined.