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)