mirror of https://github.com/mkerrisk/man-pages
109 lines
3.0 KiB
Plaintext
109 lines
3.0 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "BSD_SIGNAL" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" bsd_signal
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.SH NAME
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bsd_signal \- simplified signal facilities
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.SH SYNOPSIS
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.LP
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\fB#include <signal.h>
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.br
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.sp
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void (*bsd_signal(int\fP \fIsig\fP\fB, void (*\fP\fIfunc\fP\fB)(int)))(int);
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\fP
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\fB
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.br
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\fP
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.SH DESCRIPTION
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.LP
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The \fIbsd_signal\fP() function provides a partially compatible interface
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for programs written to historical system interfaces
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(see APPLICATION USAGE).
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.LP
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The function call \fIbsd_signal\fP(\fIsig\fP, \fIfunc\fP) shall be
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equivalent to the following:
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.sp
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.RS
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.nf
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\fBvoid (*bsd_signal(int sig, void (*func)(int)))(int)
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{
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struct sigaction act, oact;
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.sp
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act.sa_handler =\fP \fIfunc\fP\fB;
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act.sa_flags = SA_RESTART;
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sigemptyset(&act.sa_mask);
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sigaddset(&act.sa_mask,\fP \fIsig\fP\fB);
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if (sigaction(\fP\fIsig\fP\fB, &act, &oact) == -1)
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return(SIG_ERR);
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return(oact.sa_handler);
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}
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\fP
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.fi
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.RE
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.LP
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The handler function should be declared:
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.sp
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.RS
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.nf
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\fBvoid handler(int\fP \fIsig\fP\fB);
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\fP
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.fi
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.RE
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.LP
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where \fIsig\fP is the signal number. The behavior is undefined if
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\fIfunc\fP is a function that takes more than one argument,
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or an argument of a different type.
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.SH RETURN VALUE
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.LP
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Upon successful completion, \fIbsd_signal\fP() shall return the previous
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action for \fIsig\fP. Otherwise, SIG_ERR shall be
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returned and \fIerrno\fP shall be set to indicate the error.
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.SH ERRORS
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.LP
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Refer to \fIsigaction\fP() .
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.LP
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\fIThe following sections are informative.\fP
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.SH EXAMPLES
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.LP
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None.
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.SH APPLICATION USAGE
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.LP
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This function is a direct replacement for the BSD \fIsignal\fP() function
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for simple
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applications that are installing a single-argument signal handler
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function. If a BSD signal handler function is being installed
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that expects more than one argument, the application has to be modified
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to use \fIsigaction\fP(). The \fIbsd_signal\fP() function differs
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from \fIsignal\fP() in that the SA_RESTART flag is set and the SA_RESETHAND
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is clear when
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\fIbsd_signal\fP() is used. The state of these flags is not specified
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for \fIsignal\fP().
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.LP
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It is recommended that new applications use the \fIsigaction\fP()
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function.
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.SH RATIONALE
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.LP
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None.
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIsigaction\fP() , \fIsigaddset\fP() , \fIsigemptyset\fP() , \fIsignal\fP()
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, the Base Definitions volume of
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IEEE\ Std\ 1003.1-2001, \fI<signal.h>\fP
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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