Manpages - bsd_signal.3

bsd_signal - signal handling with BSD semantics

  #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

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.

The bsd_signal*() function returns the previous value of the signal handler, or *SIG_ERR on error.

As for *signal*(2).

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

4.2BSD, POSIX.1-2001. POSIX.1-2008 removes the specification of *bsd_signal*(), recommending the use of *sigaction*(2) instead.

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.

*sigaction*(2), *signal*(2), *sysv_signal*(3), *signal*(7)

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