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115 lines
3.5 KiB
Plaintext
115 lines
3.5 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "POSIX_FADVISE" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" posix_fadvise
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.SH NAME
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posix_fadvise \- file advisory information (\fBADVANCED REALTIME\fP)
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.SH SYNOPSIS
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.LP
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\fB#include <fcntl.h>
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.br
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.sp
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int posix_fadvise(int\fP \fIfd\fP\fB, off_t\fP \fIoffset\fP\fB, size_t\fP
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\fIlen\fP\fB, int\fP \fIadvice\fP\fB);
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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 \fIposix_fadvise\fP() function shall advise the implementation
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on the expected behavior of the application with respect to
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the data in the file associated with the open file descriptor, \fIfd\fP,
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starting at \fIoffset\fP and continuing for \fIlen\fP
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bytes. The specified range need not currently exist in the file. If
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\fIlen\fP is zero, all data following \fIoffset\fP is
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specified. The implementation may use this information to optimize
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handling of the specified data. The \fIposix_fadvise\fP()
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function shall have no effect on the semantics of other operations
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on the specified data, although it may affect the performance of
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other operations.
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.LP
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The advice to be applied to the data is specified by the \fIadvice\fP
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parameter and may be one of the following values:
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.TP 7
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POSIX_FADV_NORMAL
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.sp
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Specifies that the application has no advice to give on its behavior
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with respect to the specified data. It is the default
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characteristic if no advice is given for an open file.
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.TP 7
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POSIX_FADV_SEQUENTIAL
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.sp
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Specifies that the application expects to access the specified data
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sequentially from lower offsets to higher offsets.
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.TP 7
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POSIX_FADV_RANDOM
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.sp
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Specifies that the application expects to access the specified data
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in a random order.
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.TP 7
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POSIX_FADV_WILLNEED
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.sp
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Specifies that the application expects to access the specified data
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in the near future.
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.TP 7
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POSIX_FADV_DONTNEED
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.sp
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Specifies that the application expects that it will not access the
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specified data in the near future.
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.TP 7
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POSIX_FADV_NOREUSE
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.sp
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Specifies that the application expects to access the specified data
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once and then not reuse it thereafter.
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.sp
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.LP
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These values are defined in \fI<fcntl.h>\fP.
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.SH RETURN VALUE
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.LP
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Upon successful completion, \fIposix_fadvise\fP() shall return zero;
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otherwise, an error number shall be returned to indicate
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the error.
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.SH ERRORS
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.LP
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The \fIposix_fadvise\fP() function shall fail if:
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.TP 7
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.B EBADF
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The \fIfd\fP argument is not a valid file descriptor.
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.TP 7
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.B EINVAL
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The value of \fIadvice\fP is invalid.
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.TP 7
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.B ESPIPE
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The \fIfd\fP argument is associated with a pipe or FIFO.
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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 \fIposix_fadvise\fP() function is part of the Advisory Information
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option and need not be provided on all
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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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\fIposix_madvise\fP() , the Base Definitions volume of IEEE\ Std\ 1003.1-2001,
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\fI<fcntl.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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