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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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POSIX_FADVISE(3P) POSIX Programmer's Manual POSIX_FADVISE(3P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
posix_fadvise — file advisory information (ADVANCED REALTIME)
#include <fcntl.h>
int posix_fadvise(int fd, off_t offset, off_t len, int advice);
The posix_fadvise() function shall advise the implementation on the
expected behavior of the application with respect to the data in the
file associated with the open file descriptor, fd, starting at offset
and continuing for len bytes. The specified range need not currently
exist in the file. If len is zero, all data following offset is
specified. The implementation may use this information to optimize
handling of the specified data. The posix_fadvise() function shall
have no effect on the semantics of other operations on the specified
data, although it may affect the performance of other operations.
The advice to be applied to the data is specified by the advice
parameter and may be one of the following values:
POSIX_FADV_NORMAL
Specifies that the application has no advice to give on its
behavior with respect to the specified data. It is the default
characteristic if no advice is given for an open file.
POSIX_FADV_SEQUENTIAL
Specifies that the application expects to access the specified
data sequentially from lower offsets to higher offsets.
POSIX_FADV_RANDOM
Specifies that the application expects to access the specified
data in a random order.
POSIX_FADV_WILLNEED
Specifies that the application expects to access the specified
data in the near future.
POSIX_FADV_DONTNEED
Specifies that the application expects that it will not access
the specified data in the near future.
POSIX_FADV_NOREUSE
Specifies that the application expects to access the specified
data once and then not reuse it thereafter.
These values are defined in <fcntl.h>.
Upon successful completion, posix_fadvise() shall return zero;
otherwise, an error number shall be returned to indicate the error.
The posix_fadvise() function shall fail if:
EBADF The fd argument is not a valid file descriptor.
EINVAL The value of advice is invalid, or the value of len is less
than zero.
ESPIPE The fd argument is associated with a pipe or FIFO.
The following sections are informative.
None.
The posix_fadvise() function is part of the Advisory Information
option and need not be provided on all implementations.
None.
None.
posix_madvise(3p)
The Base Definitions volume of POSIX.1‐2008, fcntl.h(0p)
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 POSIX_FADVISE(3P)
Pages that refer to this page: fcntl.h(0p), posix_madvise(3p)
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