Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
POSIX_FALLOCATE(2)        FreeBSD System Calls Manual       POSIX_FALLOCATE(2)

NAME
     posix_fallocate - pre-allocate storage for a range in a file

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <fcntl.h>

     int
     posix_fallocate(int fd, off_t offset, off_t len);

DESCRIPTION
     Required storage for the range offset to offset + len in the file
     referenced by fd is guarateed to be allocated upon successful return.
     That is, if posix_fallocate() returns successfully, subsequent writes to
     the specified file data will not fail due to lack of free space on the
     file system storage media.  Any existing file data in the specified range
     is unmodified.  If offset + len is beyond the current file size, then
     posix_fallocate() will adjust the file size to offset + len.  Otherwise,
     the file size will not be changed.

     Space allocated by posix_fallocate() will be freed by a successful call
     to creat(2) or open(2) that truncates the size of the file.  Space
     allocated via posix_fallocate() may be freed by a successful call to
     ftruncate(2) that reduces the file size to a size smaller than offset +
     len.

RETURN VALUES
     If successful, posix_fallocate() returns zero.  It returns -1 on failure,
     and sets errno to indicate the error.

ERRORS
     Possible failure conditions:

     [EBADF]            The fd argument is not a valid file descriptor.

     [EBADF]            The fd argument references a file that was opened
                        without write permission.

     [EFBIG]            The value of offset + len is greater than the maximum
                        file size.

     [EINTR]            A signal was caught during execution.

     [EINVAL]           The len argument was zero or the offset argument was
                        less than zero.

     [EIO]              An I/O error occurred while reading from or writing to
                        a file system.

     [ENODEV]           The fd argument does not refer to a regular file.

     [ENOSPC]           There is insufficient free space remaining on the file
                        system storage media.

     [ESPIPE]           The fd argument is associated with a pipe or FIFO.

SEE ALSO
     creat(2), ftruncate(2), open(2), unlink(2)

STANDARDS
     The posix_fallocate() system call conforms to IEEE Std 1003.1-2004
     (``POSIX.1'').

HISTORY
     The posix_fallocate() function appeared in FreeBSD 9.0.

AUTHORS
     posix_fallocate() and this manual page were initially written by Matthew
     Fleming <mdf@FreeBSD.org>.

FreeBSD 11.0-PRERELEASE         April 13, 2011         FreeBSD 11.0-PRERELEASE

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS | HISTORY | AUTHORS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=posix_fallocate&sektion=2&manpath=FreeBSD+8.3-RELEASE>

home | help