truncate(S)
truncate, truncate64, ftruncate, ftruncate64 --
set a file to a specified length
Synopsis
#include <unistd.h>
int truncate (const char path, off_t length);
int truncate64 (const char path, off64_t length);
int ftruncate (int fildes, off_t length);
int ftruncate64 (int fildes, off64_t length);
Description
The file whose name is given by path or referenced by the
descriptor fildes has its size set to length bytes.
If the file was previously longer than length,
bytes past length will no longer be accessible.
If it was shorter, bytes from the
EOF
before the call to the
EOF
after the call will be read in as zeros.
The effective user
ID
of the process must have write permission for
the file, and
for ftruncate the file must be open for writing.
Return values
Upon successful completion, a value of 0 is returned.
Otherwise, a value of -1 is returned and
errno
is set to indicate the error.
truncate and truncate64 fail if one
or more of the following are true:
EACCES-
Search permission is denied on a component of the path prefix.
EACCES-
Write permission is denied for the file referred to by
path.
EFAULT-
path
points outside the process's allocated address space.
EFBIG-
An attempt is made to write a file that exceeds the
process's file size limit or the maximum file size
(see
getrlimit(S)
and
ulimit(S)).
EINTR-
A signal was caught during execution of the truncate or
truncate64 routines.
EINVAL-
path
is not an ordinary file.
EIO-
An I/O error occurred while reading from or writing to the file system.
EISDIR-
The file referred to by
path
is a directory.
ELOOP-
Too many symbolic links were encountered in translating
path.
EMFILE-
The maximum number of file descriptors available to the process has been
reached.
EMULTIHOP-
Components of
path
require hopping to multiple remote machines
and file system type does not allow it.
ENAMETOOLONG-
The length of a path component
exceeds {NAME_MAX} characters,
or the length of
path
exceeds {PATH_MAX} characters.
ENFILE-
Could not allocate any more space for the system file table.
ENOENT-
Either a component of the path prefix or the file referred to by
path
does not exist.
ENOLINK-
path
points to a remote machine and the link to that machine is no longer
active.
ENOTDIR-
A component of the path prefix of
path
is not a directory.
EROFS-
The file referred to by
path
resides on a read-only file system.
ETXTBSY-
The file referred to by
path
is a pure procedure (shared text) file that is being executed.
ftruncate fails if the following is true:
EFBIG-
The file is a regular file and length is greater than the
offset maximum established in the open file descriptor
associated with fildes.
ftruncate and ftruncate64
fail if one or more of the following are true:
EAGAIN-
The file exists, mandatory file/record locking is set, and there are
outstanding record locks on the file (see
chmod(S)).
EBADF-
fildes
is not a file descriptor open for writing.
EINTR-
A signal was caught during execution of the ftruncate or
ftruncate64 routines.
EIO-
An I/O error occurred while reading from or writing to the file system.
ENOLINK-
fildes
points to a remote machine and the link to that machine is no longer
active.
EINVAL-
fildes
does not correspond to an ordinary file.
In general, the system supports blocking truncates,
as described in
fcntl(S),
which may result in EDEADLK being set.
References
fcntl(S),
intro(S),
open(S)
Notices
Considerations for large file support
truncate64 and ftruncate64 support large files,
but are otherwise identical
to truncate and ftruncate, respectively.
For details on programming for large file capable applications, see
``Large File Support''
on intro(S).
© 2005 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 - 01 June 2005