Copyright (c)2006,2009 YAMAMOTO Takashi,
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.Dd February 4, 2013 .Dt POSIX_FADVISE 2 .Os .Sh NAME .Nm posix_fadvise .Nd hint at the future access pattern of a file ------------------------------------------------------------
.Sh LIBRARY .Lb libc ------------------------------------------------------------
.Sh SYNOPSIS n fcntl.h .Ft int .Fn posix_fadvise "int fd" "off_t offset" "off_t size" "int hint" ------------------------------------------------------------
.Sh DESCRIPTION .Fn posix_fadvise hints at the application's access pattern to the file and range given by the file descriptor, .Fa fd , and .Fa offset and .Fa size . If .Fa size is zero, it means to the end of file.
p .Fa hint should be one of the following:
p l -tag -offset indent -width POSIX_FADV_SEQUENTIAL -compact t POSIX_FADV_NORMAL No hint. (default) t POSIX_FADV_RANDOM Random access. t POSIX_FADV_SEQUENTIAL Sequential access. (from lower offset to higher offset.) t POSIX_FADV_WILLNEED Will be accessed. t POSIX_FADV_DONTNEED Will not be accessed. t POSIX_FADV_NOREUSE Will be accessed just once. .El
p
Calling
.Fn posix_fadvise
doesn't alter the semantics of the operations,
it is only a matter of performance.
------------------------------------------------------------
.Sh RETURN VALUES
On success,
.Fn posix_fadvise
returns 0.
Otherwise, it returns an error number.
------------------------------------------------------------
.Sh SEE ALSO
.Xr errno 2 ,
.Xr madvise 2
------------------------------------------------------------
.Sh BUGS
For
.Dv POSIX_FADV_NORMAL ,
.Dv POSIX_FADV_RANDOM ,
and
.Dv POSIX_FADV_SEQUENTIAL ,
the current implementation ignores
.Fa offset
and
.Fa size ,
and applies the hint to the whole file.