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)