Manpages - sysv_signal.3

sysv_signal - signal handling with System V semantics

  #define _GNU_SOURCE /* See feature_test_macros(7) */
  #include <signal.h>

  typedef void (*sighandler_t)(int);

  sighandler_t sysv_signal(int signum, sighandler_t handler);

The *sysv_signal*() function takes the same arguments, and performs the same task, as *signal*(2).

However *sysv_signal*() provides the System V unreliable signal semantics, that is: a) the disposition of the signal is reset to the default when the handler is invoked; b) delivery of further instances of the signal is not blocked while the signal handler is executing; and c) if the handler interrupts (certain) blocking system calls, then the system call is not automatically restarted.

The sysv_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).

This function is nonstandard.

Use of *sysv_signal*() should be avoided; use *sigaction*(2) instead.

On older Linux systems, *sysv_signal*() and *signal*(2) were equivalent. But on newer systems, *signal*(2) provides reliable 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), *bsd_signal*(3), *signal*(7)

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