int
     truncate(const char *path, off_t length);

     int
     ftruncate(int fd, off_t length);

DESCRIPTION

     Truncate() causes the file named by path or referenced by fd to be trun-
     cated or extended to length bytes in size.  If the file previously 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 ftruncate(), the file must be open for writing.

RETURN VALUES

     A value of 0 is returned if the call succeeds.  If the call fails a -1 is
     returned, and the global variable errno specifies the error.

ERRORS

     Truncate() succeeds unless:

     [ENOTDIR]          A component of the path prefix is not a directory.

     [ENAMETOOLONG]     A component of a pathname exceeded {NAME_MAX} charac-
                        ters, or an entire path name exceeded {PATH_MAX} char-
                        acters.

     [ENOENT]           The named file does not exist.

     [EACCES]           Search permission is denied for a component of the
                        path prefix.

     [EACCES]           The named file is not writable by the user.

     [ELOOP]            Too many symbolic links were encountered in translat-
                        ing the pathname.

     [EISDIR]           The named file is a directory.

     [EROFS]            The named file resides on a read-only file system.

     [ETXTBSY]          The file is a pure procedure (shared text) file that
                        is being executed.

     [EIO]              An I/O error occurred updating the inode.

     [EFAULT]           Path points outside the process's allocated address
                        space.

     Ftruncate() succeeds unless:

     [EBADF]            The fd is not a valid descriptor.

HISTORY

     The truncate() and ftruncate() function calls appeared in 4.2BSD.

4.2 Berkeley Distribution        June 4, 1993        4.2 Berkeley Distribution