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



NAME
       bsd_signal - signal handling with BSD semantics

SYNOPSIS
       #include <signal.h>

       typedef void (*sighandler_t)(int);

       sighandler_t bsd_signal(int signum, sighandler_t handler);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       bsd_signal():
           Since glibc 2.26:
               _XOPEN_SOURCE >= 500
                   && ! (_POSIX_C_SOURCE >= 200112L)
           Glibc 2.25 and earlier:
               _XOPEN_SOURCE

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  sys-
       tem  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 han-
       dler, or SIG_ERR on error.

ERRORS
       As for signal(2).

ATTRIBUTES
       For   an   explanation   of   the  terms  used  in  this  section,  see
       attributes(7).

       +-------------+---------------+---------+
       |Interface    | Attribute     | Value   |
       +-------------+---------------+---------+
       |bsd_signal() | Thread safety | MT-Safe |
       +-------------+---------------+---------+
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 4.16 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/.



                                  2017-09-15                     BSD_SIGNAL(3)