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78 lines
2.7 KiB
Plaintext
78 lines
2.7 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "SEM_CLOSE" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" sem_close
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.SH NAME
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sem_close \- close a named semaphore (\fBREALTIME\fP)
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.SH SYNOPSIS
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.LP
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\fB#include <semaphore.h>
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.br
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.sp
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int sem_close(sem_t *\fP\fIsem\fP\fB); \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 \fIsem_close\fP() function shall indicate that the calling process
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is finished using the named semaphore indicated by
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\fIsem\fP. The effects of calling \fIsem_close\fP() for an unnamed
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semaphore (one created by \fIsem_init\fP()) are undefined. The \fIsem_close\fP()
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function shall deallocate (that is, make
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available for reuse by a subsequent \fIsem_open\fP() by this process)
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any system
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resources allocated by the system for use by this process for this
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semaphore. The effect of subsequent use of the semaphore
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indicated by \fIsem\fP by this process is undefined. If the semaphore
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has not been removed with a successful call to \fIsem_unlink\fP(),
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then \fIsem_close\fP() has no effect on the state of the semaphore.
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If the
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\fIsem_unlink\fP() function has been successfully invoked for \fIname\fP
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after the
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most recent call to \fIsem_open\fP() with O_CREAT for this semaphore,
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then when all
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processes that have opened the semaphore close it, the semaphore is
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no longer accessible.
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.SH RETURN VALUE
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.LP
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Upon successful completion, a value of zero shall be returned. Otherwise,
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a value of -1 shall be returned and \fIerrno\fP set
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to indicate the error.
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.SH ERRORS
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.LP
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The \fIsem_close\fP() function shall fail if:
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.TP 7
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.B EINVAL
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The \fIsem\fP argument is not a valid semaphore descriptor.
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.sp
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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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The \fIsem_close\fP() function is part of the Semaphores option and
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need not be available on all implementations.
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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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\fIsemctl\fP() , \fIsemget\fP() , \fIsemop\fP()
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, \fIsem_init\fP() , \fIsem_open\fP() , \fIsem_unlink\fP() , the Base
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Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<semaphore.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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