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BSD_SIGNAL(3)              Linux Programmer's Manual             BSD_SIGNAL(3)



NAME
       bsd_signal - signal handling with BSD semantics

SYNOPSIS
       #define _XOPEN_SOURCE
       #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 inter-
       rupts 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 sigac-
       tion(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 only defined if the _GNU_SOURCE feature test macro is
       defined.

SEE ALSO
       sigaction(2), signal(2), sysv_signal(3), feature_test_macros(7), signal(7)

COLOPHON
       This page is part of release 3.22 of the Linux man-pages project.  A description of the project,  and  informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



                                  2009-03-15                     BSD_SIGNAL(3)