coreutils/src/dd.c

1246 skip_via_lseek (char const *filename, int fdesc, off_t offset, int whence)
1250   bool got_original_tape_position = (ioctl (fdesc, MTIOCGET, &s1) == 0);
1254   off_t new_position = lseek (fdesc, offset, whence);
1257       && ioctl (fdesc, MTIOCGET, &s2) == 0
1276    nonzero.  If fdesc is STDIN_FILENO, advance the input offset.
1281 skip (int fdesc, char const *file, uintmax_t records, size_t blocksize,
1292       && 0 <= skip_via_lseek (file, fdesc, offset, SEEK_CUR))
1294       if (fdesc == STDIN_FILENO)
1324       if ((skip_via_lseek (file, fdesc, 0, SEEK_END)) >= 0)
1341           if (fdesc == STDIN_FILENO)
1353           ssize_t nread = iread_fnc (fdesc, buf, blocksize);
1356               if (fdesc == STDIN_FILENO)
1372           if (fdesc == STDIN_FILENO)