HP-UX Reference (11i v1 00/12) - 2 System Calls (vol 5)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man2/!!!intro.2
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t
truncate(2) truncate(2)
NAME
ftruncate, truncate - truncate a file to a specified length
SYNOPSIS
#include <unistd.h>
int ftruncate(int fildes, off_t length);
int truncate(const char *path, off_t length);
DESCRIPTION
The ftruncate() function causes the regular file referenced by fildes to have a size of length bytes.
The truncate() function causes the regular file named by path to have a size of length bytes.
The effect of ftruncate() and truncate() on other types of files is unspecified. If the file previously
was larger than length, the extra data is lost. If it was previously shorter than length, bytes between the
old and new lengths are read as zeroes. With ftruncate() , the file must be open for writing; for trun-
cate()
, the process must have write permission for the file.
If the request would cause the file size to exceed the soft file size limit for the process, the request will fail
and the implementation will generate the
SIGXFSZ signal for the process.
These functions do not modify the file offset for any open file descriptions associated with the file. On suc-
cessful completion, if the file size is changed, these functions will mark for update the st_ctime and
st_mtime fields of the file, and if the file is a regular file, the
S_ISUID and S_ISGID bits of the file mode
may be cleared.
RETURN VALUE
Upon successful completion,
ftruncate() and truncate() returns 0. Otherwise a −1 is returned, and
errno is set to indicate the error.
ERRORS
The ftruncate() and truncate() functions will fail if:
[EINTR] A signal was caught during execution.
[EINVAL] The length argument was less than 0.
[EFBIG] or [EINVAL] The length argument was greater than the maximum file size.
[EIO] An I/O error occurred while reading from or writing to a file system.
The
ftruncate() function will fail if:
[EBADF] or [EINVAL] The fildes argument is not a file descriptor open for writing.
[EINVAL] The fildes argument references a file that was opened without write per-
mission.
The
truncate() function will fail if:
[EACCES] A component of the path prefix denies search permission, or write permis-
sion is denied on the file.
[EISDIR] The named file is a directory.
[ELOOP] Too many symbolic links were encountered in resolving path.
[ENAMETOOLONG] The length of the specified pathname exceeds
PATH_MAX bytes, or the
length of a component of the pathname exceeds
NAME_MAX bytes.
[ENOENT] A component of path does not name an existing file or path is an empty
string.
[ENOTDIR] A component of the path prefix of path is not a directory.
[EROFS] The named file resides on a read-only file system.
The truncate() function may fail if:
[ENAMETOOLONG] Pathname resolution of a symbolic link produced an intermediate result
whose length exceeds {PATH_MAX}.
Section 2−−410 − 1 − HP-UX Release 11i: December 2000
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