PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

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

PROLOG         top

       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         top

       posix_fallocate — file space control (ADVANCED REALTIME)

SYNOPSIS         top

       #include <fcntl.h>

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

DESCRIPTION         top

       The posix_fallocate() function shall ensure that any required storage
       for regular file data starting at offset and continuing for len bytes
       is allocated on the file system storage media. If posix_fallocate()
       returns successfully, subsequent writes to the specified file data
       shall not fail due to the lack of free space on the file system
       storage media.

       If the offset+len is beyond the current file size, then
       posix_fallocate() shall adjust the file size to offset+len.
       Otherwise, the file size shall not be changed.

       It is implementation-defined whether a previous posix_fadvise() call
       influences allocation strategy.

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

RETURN VALUE         top

       Upon successful completion, posix_fallocate() shall return zero;
       otherwise, an error number shall be returned to indicate the error.

ERRORS         top

       The posix_fallocate() function shall fail if:

       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 is less than zero, or the offset argument is
              less than zero, or the underlying file system does not support
              this operation.

       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.

       The posix_fallocate() function may fail if:

       EINVAL The len argument is zero.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       The posix_fallocate() function is part of the Advisory Information
       option and need not be provided on all implementations.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       creat(3p), ftruncate(3p), open(3p), unlink(3p)

       The Base Definitions volume of POSIX.1‐2008, fcntl.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                 2013                 POSIX_FALLOCATE(3P)