Messages in this thread |  | | Date | Fri, 17 Nov 2000 15:59:13 -0800 | From | "H . J . Lu" <> | Subject | lseek/llseek allows the negative offset |
| |
# gcc x.c # ./a.out lseek on -100000: -100000 write: File too large
Should kernel allow negative offsets for lseek/llseek?
-- H.J. Lu (hjl@valinux.com) --- #include <fcntl.h> #include <unistd.h> #include <stdio.h>
extern loff_t llseek (int fd, loff_t offset, int whence);
int main () { int fd = open ("/tmp/foo.out", O_CREAT | O_RDWR, 0600); off_t res, pos; loff_t lres, lpos; char buffer [] = "negative offset";
if (fd < 0) { perror ("open"); return 1; }
pos = -100000; res = lseek (fd, pos, SEEK_SET); if (res == (off_t) -1L) { perror ("lseek"); close (fd); return 1; } printf ("lseek on %ld: %ld\n", pos, res);
if (write (fd, buffer, sizeof (buffer)) != sizeof (buffer)) { perror ("write"); close (fd); return 1; }
lpos = -100000LL; lres = llseek (fd, lpos, SEEK_SET); if (lres == (loff_t) -1L) { perror ("llseek"); close (fd); return 1; }
printf ("llseek on %lld: %lld\n", lpos, lres);
if (write (fd, buffer, sizeof (buffer)) != sizeof (buffer)) { perror ("write"); close (fd); return 1; }
close (fd);
return 0; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
|  |