NAME

       bsd_signal - signal handling with BSD semantics

SYNOPSIS

       #define _XOPEN_SOURCE       /* See feature_test_macros(7) */
       #include <signal.h>

       typedef void (*sighandler_t)(int);

       sighandler_t bsd_signal(int signum, sighandler_t handler);

DESCRIPTION

       The bsd_signal() function takes the same arguments, and performs the same task, as signal(2).

       The  difference  between the two is that bsd_signal() is guaranteed to provide reliable signal semantics,
       that is: a) the disposition of the signal is not reset to the default when the  handler  is  invoked;  b)
       delivery  of  further instances of the signal is blocked while the signal handler is executing; and c) if
       the handler interrupts a blocking system call, then  the  system  call  is  automatically  restarted.   A
       portable application cannot rely on signal(2) to provide these guarantees.

RETURN VALUE

       The bsd_signal() function returns the previous value of the signal handler, or SIG_ERR on error.

ERRORS

       As for signal(2).

CONFORMING TO

       4.2BSD,  POSIX.1-2001.   POSIX.1-2008  removes the specification of bsd_signal(), recommending the use of
       sigaction(2) instead.

NOTES

       Use of bsd_signal() should be avoided; use sigaction(2) instead.

       On modern Linux systems, bsd_signal() and signal(2) are equivalent.   But  on  older  systems,  signal(2)
       provided unreliable signal semantics; see signal(2) for details.

       The  use  of  sighandler_t  is a GNU extension; this type is defined only if the _GNU_SOURCE feature test
       macro is defined.

SEE ALSO

       sigaction(2), signal(2), sysv_signal(3), signal(7)

COLOPHON

       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

                                                   2009-03-15                                      BSD_SIGNAL(3)