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diff --git a/man3p/sigemptyset.3p b/man3p/sigemptyset.3p new file mode 100644 index 000000000..97be194bc --- /dev/null +++ b/man3p/sigemptyset.3p @@ -0,0 +1,93 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "SIGEMPTYSET" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" sigemptyset +.SH NAME +sigemptyset \- initialize and empty a signal set +.SH SYNOPSIS +.LP +\fB#include <signal.h> +.br +.sp +int sigemptyset(sigset_t *\fP\fIset\fP\fB); \fP +\fB +.br +\fP +.SH DESCRIPTION +.LP +The \fIsigemptyset\fP() function initializes the signal set pointed +to by \fIset\fP, such that all signals defined in +IEEE\ Std\ 1003.1-2001 are excluded. +.SH RETURN VALUE +.LP +Upon successful completion, \fIsigemptyset\fP() shall return 0; otherwise, +it shall return -1 and set \fIerrno\fP to indicate +the error. +.SH ERRORS +.LP +No errors are defined. +.LP +\fIThe following sections are informative.\fP +.SH EXAMPLES +.LP +None. +.SH APPLICATION USAGE +.LP +None. +.SH RATIONALE +.LP +The implementation of the \fIsigemptyset\fP() (or \fIsigfillset\fP()) +function +could quite trivially clear (or set) all the bits in the signal set. +Alternatively, it would be reasonable to initialize part of +the structure, such as a version field, to permit binary-compatibility +between releases where the size of the set varies. For such +reasons, either \fIsigemptyset\fP() or \fIsigfillset\fP() must be +called prior to any +other use of the signal set, even if such use is read-only (for example, +as an argument to \fIsigpending\fP()). This function is not intended +for dynamic allocation. +.LP +The \fIsigfillset\fP() and \fIsigemptyset\fP() functions require that +the resulting +signal set include (or exclude) all the signals defined in this volume +of IEEE\ Std\ 1003.1-2001. Although it is outside +the scope of this volume of IEEE\ Std\ 1003.1-2001 to place this requirement +on signals that are implemented as extensions, +it is recommended that implementation-defined signals also be affected +by these functions. However, there may be a good reason for +a particular signal not to be affected. For example, blocking or ignoring +an implementation-defined signal may have undesirable +side effects, whereas the default action for that signal is harmless. +In such a case, it would be preferable for such a signal to +be excluded from the signal set returned by \fIsigfillset\fP(). +.LP +In early proposals there was no distinction between invalid and unsupported +signals (the names of optional signals that were not +supported by an implementation were not defined by that implementation). +The [EINVAL] error was thus specified as a required error +for invalid signals. With that distinction, it is not necessary to +require implementations of these functions to determine whether +an optional signal is actually supported, as that could have a significant +performance impact for little value. The error could +have been required for invalid signals and optional for unsupported +signals, but this seemed unnecessarily complex. Thus, the error +is optional in both cases. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fISignal Concepts\fP , \fIsigaction\fP() , \fIsigaddset\fP() , \fIsigdelset\fP() +, \fIsigfillset\fP() , \fIsigismember\fP() , \fIsigpending\fP() , +\fIsigprocmask\fP() , \fIsigsuspend\fP() , the Base Definitions volume +of IEEE\ Std\ 1003.1-2001, \fI<signal.h>\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html . |