seq_get_buf
size_t size = seq_get_buf(m, &buf);
size_t size = seq_get_buf(m, &buf);
size_t size = seq_get_buf(m, &buf);
size_t size = seq_get_buf(m, &buf);
size = seq_get_buf(m, &buffer);
count = seq_get_buf(sf, &buf);
size_t n = seq_get_buf(m, &bufp);