huschi.net

POSIX_FADVISE(3P)          POSIX Programmer's Manual         POSIX_FADVISE(3P)

PROLOG
       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.
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  speci-
       fied.  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 parame-
       ter 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>.
RETURN VALUE
       Upon successful completion, posix_fadvise() shall return  zero;  other-
       wise, 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 Technology
       --  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(3P)