SIGPAUSE(3)               (2017-09-15)                SIGPAUSE(3)

     NAME
          sigpause - atomically release blocked signals and wait for
          interrupt

     SYNOPSIS
          #include <signal.h>

          int sigpause(int sigmask);  /* BSD (but see NOTES) */

          int sigpause(int sig);      /* System V / UNIX 95 */

     DESCRIPTION
          Don't use this function.  Use sigsuspend(2) instead.

          The function sigpause() is designed to wait for some signal.
          It changes the process's signal mask (set of blocked sig-
          nals), and then waits for a signal to arrive.  Upon arrival
          of a signal, the original signal mask is restored.

     RETURN VALUE
          If sigpause() returns, it was interrupted by a signal and
          the return value is -1 with errno set to EINTR.

     ATTRIBUTES
          For an explanation of the terms used in this section, see
          attributes(7).  allbox; lb lb lb l l l.
          Interface Attribute Value T{ sigpause() T}   Thread
          safety  MT-Safe

     CONFORMING TO
          The System V version of sigpause() is standardized in
          POSIX.1-2001.  It is also specified in POSIX.1-2008, where
          it is marked obsolete.

     NOTES
        History
          The classical BSD version of this function appeared in
          4.2BSD.  It sets the process's signal mask to sigmask. UNIX
          95 standardized the incompatible System V version of this
          function, which removes only the specified signal sig from
          the process's 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 * argument
          (instead of an int).

        Linux notes
          On Linux, this routine is a system call only on the Sparc
          (sparc64) architecture.

          Glibc uses the BSD version if the _BSD_SOURCE feature test

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     SIGPAUSE(3)               (2017-09-15)                SIGPAUSE(3)

          macro is defined and none of _POSIX_SOURCE, _POSIX_C_SOURCE,
          _XOPEN_SOURCE, _GNU_SOURCE, or _SVID_SOURCE is defined.
          Otherwise, the System V version is used, and feature test
          macros must be defined as follows to obtain the declaration:

          *  Since glibc 2.26: _XOPEN_SOURCE >= 500

          *  Glibc 2.25 and earlier: _XOPEN_SOURCE

          Since glibc 2.19, only the System V version is exposed by
          <signal.h>; applications that formerly used the BSD
          sigpause() should be amended to use sigsuspend(2).

     SEE ALSO
          kill(2), sigaction(2), sigprocmask(2), sigsuspend(2),
          sigblock(3), sigvec(3), feature_test_macros(7)

     COLOPHON
          This page is part of release 5.10 of the Linux man-pages
          project.  A description of the project, information about
          reporting bugs, and the latest version of this page, can be
          found at https://www.kernel.org/doc/man-pages/.

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