bsd_signal - signal handling with BSD semantics
Contents
Attributes
For an explanation of the terms used in this section, see attributes(7).
┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
│ bsd_signal() │ Thread safety │ MT-Safe │
└─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘
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.
Errors
As for signal(2).
History
4.2BSD, POSIX.1-2001. Removed in POSIX.1-2008, recommending the use of sigaction(2) instead.
Library
Standard C library (libc, -lc)
Name
bsd_signal - signal handling with BSD semantics
Return Value
The bsd_signal() function returns the previous value of the signal handler, or SIG_ERR on error.
See Also
sigaction(2), signal(2), sysv_signal(3), signal(7) Linux man-pages 6.9.1 2024-05-02 bsd_signal(3)
Standards
None.
Synopsis
#include<signal.h>typedefvoid(*sighandler_t)(int);sighandler_tbsd_signal(intsignum,sighandler_thandler); 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
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.
