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 >= 200809L)
           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 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

       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 5.05 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/.

                                            2019-03-06                              BSD_SIGNAL(3)