#define blobmsg_for_each_attr(pos, attr, rem) \
for (rem = attr ? blobmsg_data_len(attr) : 0, \
- pos = attr ? blobmsg_data(attr) : 0; \
+ pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
rem > 0 && (blob_pad_len(pos) <= rem) && \
(blob_pad_len(pos) >= sizeof(struct blob_attr)); \
rem -= blob_pad_len(pos), pos = blob_next(pos))