bsd_signal(3)              Library Functions Manual              bsd_signal(3)

NAME
       bsd_signal - signal handling with BSD semantics

LIBRARY
       Standard C library (libc, -lc)

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 |
       +--------------------------------------------+---------------+---------+
VERSIONS
       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.

STANDARDS
       None.

HISTORY
       4.2BSD, POSIX.1-2001.  Removed in POSIX.1-2008, recommending the use of
       sigaction(2) instead.

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

Linux man-pages 6.7               2023-10-31                     bsd_signal(3)