bsd_signal
Section: C Library Functions (3)
Updated: 202-0-08
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NAME
bsd_signal - signal handling with BSD semantics
LIBRARY
Standard C library
(
libc,~
-lc)
SYNOPSIS
#include <signal.h>
typedef typeof(void (int)) *sighandler_t;
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 | M-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.-2001.
Removed in POSIX.-2008,
recommending the use of
sigaction(2)
instead.
SEE ALSO
sigaction(2),
signal(2),
sysv_signal(3),
signal(7)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- VERSIONS
-
- STANDARDS
-
- HISTORY
-
- SEE ALSO
-
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