64 lines
1.1 KiB
C
64 lines
1.1 KiB
C
#ifndef LINT
|
|
static const char rcsid[] = "$Id: ftruncate.c,v 1.1.1.1 2001/05/17 22:48:45 itojun Exp $";
|
|
#endif
|
|
|
|
/*
|
|
* ftruncate - set file size, BSD Style
|
|
*
|
|
* shortens or enlarges the file as neeeded
|
|
* uses some undocumented locking call. It is known to work on SCO unix,
|
|
* other vendors should try.
|
|
* The #error directive prevents unsupported OSes
|
|
*/
|
|
|
|
#include "port_before.h"
|
|
|
|
#if defined(M_UNIX)
|
|
#define OWN_FTRUNCATE
|
|
#include <stdio.h>
|
|
#ifdef _XOPEN_SOURCE
|
|
#undef _XOPEN_SOURCE
|
|
#endif
|
|
#ifdef _POSIX_SOURCE
|
|
#undef _POSIX_SOURCE
|
|
#endif
|
|
|
|
#include <fcntl.h>
|
|
|
|
#include "port_after.h"
|
|
|
|
int
|
|
__ftruncate(int fd, long wantsize) {
|
|
long cursize;
|
|
|
|
/* determine current file size */
|
|
if ((cursize = lseek(fd, 0L, 2)) == -1)
|
|
return (-1);
|
|
|
|
/* maybe lengthen... */
|
|
if (cursize < wantsize) {
|
|
if (lseek(fd, wantsize - 1, 0) == -1 ||
|
|
write(fd, "", 1) == -1) {
|
|
return (-1);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/* maybe shorten... */
|
|
if (wantsize < cursize) {
|
|
struct flock fl;
|
|
|
|
fl.l_whence = 0;
|
|
fl.l_len = 0;
|
|
fl.l_start = wantsize;
|
|
fl.l_type = F_WRLCK;
|
|
return (fcntl(fd, F_FREESP, &fl));
|
|
}
|
|
return (0);
|
|
}
|
|
#endif
|
|
|
|
#ifndef OWN_FTRUNCATE
|
|
int __bindcompat_ftruncate;
|
|
#endif
|