diff options
Diffstat (limited to 'man-pages-posix-2013/man3p/sighold.3p')
| -rw-r--r-- | man-pages-posix-2013/man3p/sighold.3p | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/man-pages-posix-2013/man3p/sighold.3p b/man-pages-posix-2013/man3p/sighold.3p new file mode 100644 index 0000000..2812e82 --- /dev/null +++ b/man-pages-posix-2013/man3p/sighold.3p @@ -0,0 +1,255 @@ +'\" et +.TH SIGHOLD "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. + +.SH NAME +sighold, +sigignore, +sigpause, +sigrelse, +sigset +\(em signal management +.SH SYNOPSIS +.LP +.nf +#include <signal.h> +.P +int sighold(int \fIsig\fP); +int sigignore(int \fIsig\fP); +int sigpause(int \fIsig\fP); +int sigrelse(int \fIsig\fP); +void (*sigset(int \fIsig\fP, void (*\fIdisp\fP)(int)))(int); +.fi +.SH DESCRIPTION +Use of any of these functions is unspecified in a multi-threaded +process. +.P +The +\fIsighold\fR(), +\fIsigignore\fR(), +\fIsigpause\fR(), +\fIsigrelse\fR(), +and +\fIsigset\fR() +functions provide simplified signal management. +.P +The +\fIsigset\fR() +function shall modify signal dispositions. The +.IR sig +argument specifies the signal, which may be any signal except SIGKILL +and SIGSTOP. The +.IR disp +argument specifies the signal's disposition, which may be SIG_DFL, +SIG_IGN, or the address of a signal handler. If +\fIsigset\fR() +is used, and +.IR disp +is the address of a signal handler, the system shall add +.IR sig +to the signal mask of the calling process before executing the signal +handler; when the signal handler returns, the system shall restore the +signal mask of the calling process to its state prior to the delivery +of the signal. In addition, if +\fIsigset\fR() +is used, and +.IR disp +is equal to SIG_HOLD, +.IR sig +shall be added to the +signal mask of the calling process and +.IR sig 's +disposition shall remain unchanged. If +\fIsigset\fR() +is used, and +.IR disp +is not equal to SIG_HOLD, +.IR sig +shall be removed from the signal mask of the calling process. +.P +The +\fIsighold\fR() +function shall add +.IR sig +to the signal mask of the calling process. +.P +The +\fIsigrelse\fR() +function shall remove +.IR sig +from the signal mask of the calling process. +.P +The +\fIsigignore\fR() +function shall set the disposition of +.IR sig +to SIG_IGN. +.P +The +\fIsigpause\fR() +function shall remove +.IR sig +from the signal mask of the calling process and suspend the calling process +until a signal is received. The +\fIsigpause\fR() +function shall restore the signal mask of the process to its original +state before returning. +.P +If the action for the SIGCHLD signal is set to SIG_IGN, child processes +of the +calling processes shall not be transformed into zombie processes when +they terminate. If the calling process subsequently waits for its +children, and the process has no unwaited-for children that were +transformed into zombie processes, it shall block until all of its +children terminate, and +\fIwait\fR(), +\fIwaitid\fR(), +and +\fIwaitpid\fR() +shall fail and set +.IR errno +to +.BR [ECHILD] . +.SH "RETURN VALUE" +Upon successful completion, +\fIsigset\fR() +shall return SIG_HOLD if the signal had been blocked and the signal's +previous disposition if it had not been blocked. Otherwise, SIG_ERR +shall be returned and +.IR errno +set to indicate the error. +.P +The +\fIsigpause\fR() +function shall suspend execution of the thread until a signal is +received, whereupon it shall return \(mi1 and set +.IR errno +to +.BR [EINTR] . +.P +For all other functions, upon successful completion, 0 shall be returned. +Otherwise, \(mi1 shall be returned and +.IR errno +set to indicate the error. +.SH ERRORS +These functions shall fail if: +.TP +.BR EINVAL +The +.IR sig +argument is an illegal signal number. +.P +The +\fIsigset\fR() +and +\fIsigignore\fR() +functions shall fail if: +.TP +.BR EINVAL +An attempt is made to catch a signal that cannot be caught, or to +ignore a signal that cannot be ignored. +.LP +.IR "The following sections are informative." +.SH EXAMPLES +None. +.SH "APPLICATION USAGE" +The +\fIsigaction\fR() +function provides a more comprehensive and reliable mechanism for +controlling signals; new applications should use the +\fIsigaction\fR() +function instead of the obsolescent +\fIsigset\fR() +function. +.P +The +\fIsighold\fR() +function, in conjunction with +\fIsigrelse\fR() +or +\fIsigpause\fR(), +may be used to establish critical regions of code that require the +delivery of a signal to be temporarily deferred. For broader +portability, the +\fIpthread_sigmask\fR() +or +\fIsigprocmask\fR() +functions should be used instead of the obsolescent +\fIsighold\fR() +and +\fIsigrelse\fR() +functions. +.P +For broader portability, the +\fIsigsuspend\fR() +function should be used instead of the obsolescent +\fIsigpause\fR() +function. +.SH RATIONALE +Each of these historic functions has a direct analog in the other +functions which are required to be per-thread and thread-safe (aside +from +\fIsigprocmask\fR(), +which is replaced by +\fIpthread_sigmask\fR()). +The +\fIsigset\fR() +function can be implemented as a simple wrapper for +\fIsigaction\fR(). +The +\fIsighold\fR() +function is equivalent to +\fIsigprocmask\fR() +or +\fIpthread_sigmask\fR() +with SIG_BLOCK set. The +\fIsigignore\fR() +function is equivalent to +\fIsigaction\fR() +with SIG_IGN set. The +\fIsigpause\fR() +function is equivalent to +\fIsigsuspend\fR(). +The +\fIsigrelse\fR() +function is equivalent to +\fIsigprocmask\fR() +or +\fIpthread_sigmask\fR() +with SIG_UNBLOCK set. +.SH "FUTURE DIRECTIONS" +These functions may be removed in a future version. +.SH "SEE ALSO" +.IR "Section 2.4" ", " "Signal Concepts", +.IR "\fIexec\fR\^", +.IR "\fIpause\fR\^(\|)", +.IR "\fIpthread_sigmask\fR\^(\|)", +.IR "\fIsigaction\fR\^(\|)", +.IR "\fIsignal\fR\^(\|)", +.IR "\fIsigsuspend\fR\^(\|)", +.IR "\fIwait\fR\^(\|)", +.IR "\fIwaitid\fR\^(\|)" +.P +The Base Definitions volume of POSIX.1\(hy2008, +.IR "\fB<signal.h>\fP" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, Copyright (C) 2013 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.unix.org/online.html . + +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |