-int posix_fallocate(int fd, off_t offset, off_t len)
-{
- const int BUFFER_SIZE = 256 * 1024;
- int rc = 0;
- char *buf;
- unsigned int write_len;
- unsigned int bytes_written;
- off_t bytes_remaining = len;
-
- if (len == 0 || offset < 0)
- return EINVAL;
-
- buf = malloc(BUFFER_SIZE);
-
- if (buf == NULL)
- return ENOMEM;
-
- memset(buf, 0, BUFFER_SIZE);
-
- int64_t prev_pos = _telli64(fd);
-
- if (_lseeki64(fd, offset, SEEK_SET) == -1)
- return errno;
-
- while (bytes_remaining > 0) {
- if (bytes_remaining < BUFFER_SIZE)
- write_len = (unsigned int)bytes_remaining;
- else
- write_len = BUFFER_SIZE;
-
- bytes_written = _write(fd, buf, write_len);
- if (bytes_written == -1) {
- rc = errno;
- break;
- }
-
- /* Don't allow Windows to cache the write: flush it to disk */
- _commit(fd);
-
- bytes_remaining -= bytes_written;
- }
-
- free(buf);
- _lseeki64(fd, prev_pos, SEEK_SET);
- return rc;
-}
-