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).
| Interface |
Attribute |
Value |
| bsd_signal () |
Thread safety |
MT-Safe |
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)