posix_fadvise64(2) [hpux man page]
posix_fadvise(2) System Calls Manual posix_fadvise(2) NAME
posix_fadvise(), posix_fadvise64() - file advisory information SYNOPSIS
Parameters fd The open file descriptor to which the fadvise operation applies. offset The begining of the specified range as a positive, byte offset. len The length of the specified range in bytes. advice Specifies advice to be applied to range. DESCRIPTION
The function is used to advise the system about 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. It should be noted that the effect of all hints is cumulative for a given file object. All hints will be removed on processing the last close of the file object. The function may be used for large file access by a 32-bit application built with set to 64. The advice parameter is used to convey the hint to be applied to the data and may be one of the following values: 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. Specifies that the application expects to access the specified range of data sequentially from the lower offsets to higher offsets. Specifies that the application will expect to access the specified specified range of data in a random order. Specifies that the application will expect to access the specified range of data in the near future. Specifies that the application will expect that it will not access the specified range of data in the near future. Specifies that the application will expect to access the specified range of data once and then not reuse it thereafter. These values will be defined in RETURN VALUE
Successful completion. Failure. is set to indicate the error. ERRORS
If the service fails, is set to one of the following values: The fd argument is not a valid file descriptor. The fd argument is associated with a pipe or FIFO. The posix_fadvise operation is not supported by the underlying file system. The value of advice or one of the other input values has been found to be invalid. A designated hint is not supported by the underlying file object. EXAMPLES
AUTHOR
was derived by HP from the IEEE POSIX 1003.1-2001 Standard. SEE ALSO
fadvise(2), fcntl(2), fadvise(5), fcntl(5). STANDARDS CONFORMANCE
posix_fadvise(2)
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POSIX_FADVISE(P) POSIX Programmer's Manual POSIX_FADVISE(P) NAME
posix_fadvise - file advisory information (ADVANCED REALTIME) SYNOPSIS
#include <fcntl.h> int posix_fadvise(int fd, off_t offset, size_t len, int advice); DESCRIPTION
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 charac- teristic 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>. RETURN VALUE
Upon successful completion, posix_fadvise() shall return zero; otherwise, an error number shall be returned to indicate the error. ERRORS
The posix_fadvise() function shall fail if: EBADF The fd argument is not a valid file descriptor. EINVAL The value of advice is invalid. ESPIPE The fd argument is associated with a pipe or FIFO. The following sections are informative. EXAMPLES
None. APPLICATION USAGE
The posix_fadvise() function is part of the Advisory Information option and need not be provided on all implementations. RATIONALE
None. FUTURE DIRECTIONS
None. SEE ALSO
posix_madvise() , the Base Definitions volume of IEEE Std 1003.1-2001, <fcntl.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- 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 . IEEE
/The Open Group 2003 POSIX_FADVISE(P)