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SYSV_SIGNAL

Section: Linux Programmer's Manual (3)
Updated: 2007-05-04
Index Return to Main Contents

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NAME

sysv_signal - signal handling with System V semantics  

SYNOPSIS

#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);  

DESCRIPTION

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.  

RETURN VALUE

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

ERRORS

As for signal(2).  

CONFORMING TO

This function is nonstandard.  

NOTES

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 only defined if the _GNU_SOURCE feature test macro is defined.  

SEE ALSO

sigaction(2), signal(2), bsd_signal(3), signal(7)  

COLOPHON

This page is part of release 3.35 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://man7.org/linux/man-pages/.

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Index

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

ERRORS

CONFORMING TO

NOTES

SEE ALSO

COLOPHON

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