sysv_signal3
Signal handling with system v semantics
Usage
#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <signal.h>
typedef typeof(void (int)) *sighandler_t;
sighandler_t sysv_signal(int signum, sighandler_t handler);
Library
Standard C library (libc, -lc)
Overview
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).
Attributes
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| sysv_signal() | Thread safety | MT-Safe |
Versions
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.
Releases
10 releases since Debian 5.0 (Lenny); the text changed 9 times.