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



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 sig‐
       nal(2).

       The difference between the two is that bsd_signal() is guaranteed to provide reliable sig‐
       nal  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).

ATTRIBUTES
   Multithreading (see pthreads(7))
       The bsd_signal() function is thread-safe.

CONFORMING TO
       4.2BSD, POSIX.1-2001.  POSIX.1-2008 removes the specification of bsd_signal(),  recommend‐
       ing 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 3.74 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 http://www.kernel.org/doc/man-pages/.



                                            2013-10-22                              BSD_SIGNAL(3)