Function file_write_once

lib_acl/src/stdlib/acl_vstream.c:1453–1496

}

static int file_write_once(ACL_VSTREAM *fp, const void *vptr, int dlen)
{
	int n;

	if ((fp->oflags & O_APPEND)) {
#ifdef ACL_WINDOWS
		fp->sys_offset = acl_lseek(ACL_VSTREAM_FILE(fp), 0, SEEK_END);
		if (fp->sys_offset < 0) {
			fp->errnum = acl_last_error();
			fp->flag |= ACL_VSTREAM_FLAG_ERR;
			return ACL_VSTREAM_EOF;
		}
#endif
	} else if ((fp->flag & ACL_VSTREAM_FLAG_CACHE_SEEK)
			&& fp->offset != fp->sys_offset) {

		fp->sys_offset = acl_lseek(ACL_VSTREAM_FILE(fp),
				fp->offset, SEEK_SET);
		if (fp->sys_offset == -1) {
			acl_msg_error("%s, %s(%d): lseek error(%s), "
				"offset(" ACL_FMT_I64D "), sys_offset("
				ACL_FMT_I64D ")", __FUNCTION__, __FILE__,
				__LINE__, acl_last_serror(),
				fp->offset, fp->sys_offset);

			fp->errnum = acl_last_error();
			fp->flag |= ACL_VSTREAM_FLAG_ERR;
			return ACL_VSTREAM_EOF;
		}
		fp->offset = fp->sys_offset;
	}

	n = fp->fwrite_fn(ACL_VSTREAM_FILE(fp), vptr, dlen,
			fp->rw_timeout, fp, fp->context);
	if (n > 0) {
		fp->sys_offset += n;
		fp->offset = fp->sys_offset;

		/* ��ֹ�������ڵ�������ʵ�ʲ�һ��, �����ļ�IO��Ч */
		fp->read_cnt = 0;
	}

	return n;
}

static int write_once(ACL_VSTREAM *fp, const void *vptr, int dlen)
{