New page created by splitting out from sigaction.2

Added text on effect of NULL for 'set' argument.
Added text noting effect of ignoring SIGBUS, SIGFPE, SIGILL,
       and SIGSEGV.
Noted that sigprocmask() can't be used in multithreaded process.
Fixed EINVAL error diagnostic.
Changed CONFORMING TO.

man2/sigprocmask.2

@@ -1 +1,120 @@
-.so man2/sigaction.2
+.\" Copyright (c) 2005 Michael Kerrisk
+.\" based on earlier work by faith@cs.unc.edu and 
+.\" Mike Battersby <mib@deakin.edu.au>
+.\"
+.\" Permission is granted to make and distribute verbatim copies of this
+.\" manual provided the copyright notice and this permission notice are
+.\" preserved on all copies.
+.\"
+.\" Permission is granted to copy and distribute modified versions of this
+.\" manual under the conditions for verbatim copying, provided that the
+.\" entire resulting derived work is distributed under the terms of a
+.\" permission notice identical to this one.
+.\" 
+.\" Since the Linux kernel and libraries are constantly changing, this
+.\" manual page may be incorrect or out-of-date.  The author(s) assume no
+.\" responsibility for errors or omissions, or for damages resulting from
+.\" the use of the information contained herein.  The author(s) may not
+.\" have taken the same level of care in the production of this manual,
+.\" which is licensed free of charge, as they might when working
+.\" professionally.
+.\" 
+.\" Formatted or processed versions of this manual, if unaccompanied by
+.\" the source, must acknowledge the copyright and authors of this work.
+.\"
+.\" 2005-09-15, mtk, Created new page by splitting off from sigaction.2
+.\"
+.TH SIGPROCMASK 2 2005-09-15 "Linux 2.6.13" "Linux Programmer's Manual"
+.SH NAME
+sigprocmask \- examine and change blocked signals
+.SH SYNOPSIS
+.B #include <signal.h>
+.sp 
+.BI "int sigprocmask(int " how ", const sigset_t *" set ,
+.BI "sigset_t *" oldset );
+.SH DESCRIPTION
+.BR sigprocmask ()
+is used to change the signal mask, the set of currently blocked signals.
+The behaviour of the call is dependent on the value of
+.IR how ,
+as follows.
+.RS
+.TP
+.B SIG_BLOCK
+The set of blocked signals is the union of the current set and the
+.I set
+argument.
+.TP
+.B SIG_UNBLOCK
+The signals in
+.I set
+are removed from the current set of blocked signals.  It is legal to
+attempt to unblock a signal which is not blocked.
+.TP
+.B SIG_SETMASK
+The set of blocked signals is set to the argument
+.IR set .
+.RE
+.PP
+If
+.I oldset
+is non\-null, the previous value of the signal mask is stored in
+.IR oldset .
+
+If
+.I set
+is NULL, then the signal mask is unchanged (i.e.,
+.I how
+is ignored),
+but the current value of the signal mask is nevertheless returned in
+.IR oldset 
+(it it is not NULL).
+
+The use of
+.BR sigprocmask ()
+is unspecified in a multithreaded process; see
+.BR pthread_sigmask (3).
+.SH "RETURN VALUE"
+.BR sigprocmask ()
+returns 0 on success and \-1 on error.
+.SH ERRORS
+.B EINVAL
+The value specified in
+.I how
+was invalid.
+.SH NOTES
+It is not possible to block 
+.BR SIGKILL " or " SIGSTOP .
+Attempts to do so are silently ignored.
+.PP
+If
+.BR SIGBUS ,
+.BR SIGFPE , 
+.BR SIGILL ,
+or
+.BR SIGSEGV 
+are generated
+while they are blocked, the result is undefined,
+unless the signal was generated by the
+.BR kill (2),
+.BR sigqueue (2),
+or
+.BR raise (3).
+.PP
+See
+.BR sigsetops (3)
+for details on manipulating signal sets.
+.SH "CONFORMING TO"
+POSIX.1-2001.
+.SH "SEE ALSO"
+.BR kill (2),
+.BR pause (2),
+.BR sigaction (2),
+.BR signal (2),
+.BR sigpending (2),
+.BR sigprocmask (2),
+.BR sigqueue (2),
+.BR sigsuspend (2),
+.BR pthread_sigmask (3),
+.BR sigsetops (3),
+.BR signal (7)