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 interrupts a blocking system call,
       then the system call is automatically restarted.  A portable application cannot rely on signal(2) to provide these  guar-
       antees.

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 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 3.25 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)