sigset(3) [netbsd man page]
SIGSET(3) BSD Library Functions Manual SIGSET(3) NAME
sigset -- manipulate signal dispositions LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <signal.h> void (* sigset(int sig, void (*disp)(int)))(int); DESCRIPTION
This interface is made obsolete by sigaction(2) and sigprocmask(2). The sigset() function manipulates the disposition of the signal sig. The new disposition is given in disp. If disp is one of SIG_DFL, SIG_IGN, or the address of a handler function, the disposition of sig is changed accordingly, and sig is removed from the process' signal mask. Also, if disp is the address of a handler function, sig will be added to the process' signal mask during exe- cution of the handler. If disp is equal to SIG_HOLD, sig is added to the calling process' signal mask and the disposition of sig remains unchanged. RETURN VALUES
If successful, the sigset() function returns SIG_HOLD if sig had been blocked, and the previous disposition of sig if it had not been blocked. Otherwise SIG_ERR is returned and errno is set to indicate the error. ERRORS
The sigset() function will fail if: [EINVAL] The argument sig is not a valid signal number; or an attempt is made to ignore a signal that cannot be ignored, such as SIGKILL or SIGSTOP. SEE ALSO
sigaction(2), sigprocmask(2) STANDARDS
The sigset() function conforms to IEEE Std 1003.1-2001 (``POSIX.1''). It was however marked as obsolete in the IEEE Std 1003.1-2008 (``POSIX.1'') revision of the standard. BSD
April 30, 2010 BSD
Check Out this Related Man Page
SIGSET(3) Linux Programmer's Manual SIGSET(3) NAME
sigset, sighold, sigrelse, sigignore - System V signal API SYNOPSIS
#include <signal.h> typedef void (*sighandler_t)(int); sighandler_t sigset(int sig, sighandler_t disp); int sighold(int sig); int sigrelse(int sig); int sigignore(int sig); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): sigset(), sighold(), sigrelse(), sigignore(): _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED DESCRIPTION
These functions are provided in glibc as a compatibility interface for programs that make use of the historical System V signal API. This API is obsolete: new applications should use the POSIX signal API (sigaction(2), sigprocmask(2), etc.) The sigset() function modifies the disposition of the signal sig. The disp argument can be the address of a signal handler function, or one of the following constants: SIG_DFL Reset the disposition of sig to the default. SIG_IGN Ignore sig. SIG_HOLD Add sig to the process's signal mask, but leave the disposition of sig unchanged. If disp specifies the address of a signal handler, then sig is added to the process's signal mask during execution of the handler. If disp was specified as a value other than SIG_HOLD, then sig is removed from the process's signal mask. The dispositions for SIGKILL and SIGSTOP cannot be changed. The sighold() function adds sig to the calling process's signal mask. The sigrelse() function removes sig from the calling process's signal mask. The sigignore() function sets the disposition of sig to SIG_IGN. RETURN VALUE
On success, sigset() returns SIG_HOLD if sig was blocked before the call, or the signal's previous disposition if it was not blocked before the call. On error, sigset() returns -1, with errno set to indicate the error. (But see BUGS below.) The sighold(), sigrelse(), and sigignore() functions return 0 on success; on error, these functions return -1 and set errno to indicate the error. ERRORS
For sigset() see the ERRORS under sigaction(2) and sigprocmask(2). For sighold() and sigrelse() see the ERRORS under sigprocmask(2). For sigignore(), see the errors under sigaction(2). CONFORMING TO
SVr4, POSIX.1-2001. These functions are obsolete: do not use them in new programs. POSIX.1-2008 marks sighold(), sigignore(), sigpause(), sigrelse(), and sigset() as obsolete, recommending the use of sigaction(2), sigprocmask(2), pthread_sigmask(3), and sigsuspend(2) instead. NOTES
These functions appeared in glibc version 2.1. The sighandler_t type is a GNU extension; it is used on this page only to make the sigset() prototype more easily readable. The sigset() function provides reliable signal handling semantics (as when calling sigaction(2) with sa_mask equal to 0). On System V, the signal() function provides unreliable semantics (as when calling sigaction(2) with sa_mask equal to SA_RESETHAND | SA_NODEFER). On BSD, signal() provides reliable semantics. POSIX.1-2001 leaves these aspects of signal() unspecified. See signal(2) for further details. In order to wait for a signal, BSD and System V both provided a function named sigpause(3), but this function has a different argument on the two systems. See sigpause(3) for details. BUGS
In versions of glibc before 2.2, sigset() did not unblock sig if disp was specified as a value other than SIG_HOLD. In versions of glibc before 2.5, sigset() does not correctly return the previous disposition of the signal in two cases. First, if disp is specified as SIG_HOLD, then a successful sigset() always returns SIG_HOLD. Instead, it should return the previous disposition of the sig- nal (unless the signal was blocked, in which case SIG_HOLD should be returned). Second, if the signal is currently blocked, then the return value of a successful sigset() should be SIG_HOLD. Instead, the previous disposition of the signal is returned. These problems have been fixed since glibc 2.5. SEE ALSO
kill(2), pause(2), sigaction(2), signal(2), sigprocmask(2), raise(3), sigpause(3), sigvec(3), signal(7) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2010-09-20 SIGSET(3)