129 lines
3.8 KiB
Groff
129 lines
3.8 KiB
Groff
.\" Copyright (c) 1983, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)truncate.2 8.1 (Berkeley) 6/4/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd June 4, 1993
|
|
.Dt TRUNCATE 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm truncate ,
|
|
.Nm ftruncate
|
|
.Nd truncate or extend a file to a specified length
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In unistd.h
|
|
.Ft int
|
|
.Fn truncate "const char *path" "off_t length"
|
|
.Ft int
|
|
.Fn ftruncate "int fd" "off_t length"
|
|
.Sh DESCRIPTION
|
|
.Fn Truncate
|
|
causes the file named by
|
|
.Fa path
|
|
or referenced by
|
|
.Fa fd
|
|
to be truncated or extended to
|
|
.Fa length
|
|
bytes in size. If the file
|
|
was larger than this size, the extra data
|
|
is lost.
|
|
If the file was smaller than this size,
|
|
it will be extended as if by writing bytes
|
|
with the value zero.
|
|
With
|
|
.Fn ftruncate ,
|
|
the file must be open for writing.
|
|
.Sh RETURN VALUES
|
|
.Rv -std
|
|
.Sh ERRORS
|
|
.Fn Truncate
|
|
succeeds unless:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOTDIR
|
|
A component of the path prefix is not a directory.
|
|
.It Bq Er ENAMETOOLONG
|
|
A component of a pathname exceeded 255 characters,
|
|
or an entire path name exceeded 1023 characters.
|
|
.It Bq Er ENOENT
|
|
The named file does not exist.
|
|
.It Bq Er EACCES
|
|
Search permission is denied for a component of the path prefix.
|
|
.It Bq Er EACCES
|
|
The named file is not writable by the user.
|
|
.It Bq Er ELOOP
|
|
Too many symbolic links were encountered in translating the pathname.
|
|
.It Bq Er EISDIR
|
|
The named file is a directory.
|
|
.It Bq Er EROFS
|
|
The named file resides on a read-only file system.
|
|
.It Bq Er ETXTBSY
|
|
The file is a pure procedure (shared text) file that is being executed.
|
|
.It Bq Er EIO
|
|
An I/O error occurred updating the inode.
|
|
.It Bq Er EFAULT
|
|
.Fa Path
|
|
points outside the process's allocated address space.
|
|
.El
|
|
.Pp
|
|
.Fn Ftruncate
|
|
succeeds unless:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EBADF
|
|
The
|
|
.Fa fd
|
|
is not a valid descriptor.
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa fd
|
|
references a socket, not a file.
|
|
.It Bq Er EINVAL
|
|
The
|
|
.Fa fd
|
|
is not open for writing.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr open 2
|
|
.Sh BUGS
|
|
These calls should be generalized to allow ranges
|
|
of bytes in a file to be discarded.
|
|
.Pp
|
|
Use of
|
|
.Fn truncate
|
|
to extend a file is not portable.
|
|
.Sh HISTORY
|
|
The
|
|
.Fn truncate
|
|
function call appeared in
|
|
.Bx 4.2 .
|