POSIX_FADVISE(2) NetBSD System Calls Manual POSIX_FADVISE(2)
posix_fadvise -- hint at the future access pattern of a file
Standard C Library (libc, -lc)
#include <fcntl.h> int posix_fadvise(int fd, off_t offset, off_t size, int hint);
posix_fadvise() hints at the application's access pattern to the file and range given by the file descriptor, fd, and offset and size. If size is zero, it means to the end of file. hint should be one of the following: POSIX_FADV_NORMAL No hint. (default) POSIX_FADV_RANDOM Random access. POSIX_FADV_SEQUENTIAL Sequential access. (from lower offset to higher offset.) POSIX_FADV_WILLNEED Will be accessed. POSIX_FADV_DONTNEED Will not be accessed. POSIX_FADV_NOREUSE Will be accessed just once. Calling posix_fadvise() doesn't alter the semantics of the operations, it is only a matter of performance.
On success, posix_fadvise() returns 0. Otherwise, it returns an error number.
For POSIX_FADV_NORMAL, POSIX_FADV_RANDOM, and POSIX_FADV_SEQUENTIAL, the current implementation ignores offset and size, and applies the hint to the whole file. NetBSD 9.0 February 4, 2013 NetBSD 9.0
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