xbc_init
int __init xbc_init(const char *buf, size_t size, const char **emsg, int *epos);
ret = xbc_init(data, size, &msg, &pos);
ret = xbc_init(*buf, size, &msg, NULL);
ret = xbc_init(buf, len, &msg, &pos);
ret = xbc_init(buf, size, &msg, &pos);