xref: /illumos-gate/usr/src/man/man3c/posix_fallocate.3c (revision d0fccfcda73f8b52d101bd2b0f7885a766f7e354)
te
Copyright (c) 2001, the Institute of Electrical and Electronics Engineers, Inc. and The Open Group. All Rights Reserved.
Portions Copyright (c) 2008, Sun Microsystems, Inc. All Rights Reserved.
Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at
http://www.opengroup.org/bookstore/.
The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions 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.
This notice shall appear on any product containing this material.
The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
POSIX_FALLOCATE 3C "Jul 14, 2008"
NAME
posix_fallocate - file space control
SYNOPSIS

#include <fcntl.h>

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

The posix_fallocate() function ensures 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 will 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() adjusts the file size to offset+len. Otherwise, the file size is not changed.

Space allocated with posix_fallocate() is freed by a successful call to creat(2) or open(2) that truncates the size of the file. Space allocated with posix_fallocate() may be freed by a successful call to ftruncate(3C) that reduces the file size to a size smaller than offset+len.

RETURN VALUES

Upon successful completion, posix_fallocate() returns zero. Otherwise, an error number is returned to indicate the error.

ERRORS

The posix_fallocate() function will fail if: EBADF

The fd argument is not a valid file descriptor or 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 or equal to 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.

USAGE

The posix_fallocate() function has a transitional interface for 64-bit file offsets. See lf64(5).

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Committed
MT-Level MT-Safe
Standard See standards(5).
SEE ALSO

creat(2), open(2), unlink(2), ftruncate(3C), attributes(5), standards(5)