p9pbuf_get_str
if (p9pbuf_get_str(pb, &str, &strsize))
if ((rv = p9pbuf_get_str(pb, val, strsize))) return rv; \
rv = p9pbuf_get_str(pb, &name, &size);
int p9pbuf_get_str(struct puffs_framebuf *, char **, uint16_t *);