btf__fd
LIBBPF_API int btf__fd(const struct btf *btf);
btf__set_fd(obj->btf, btf__fd(kern_btf));
if (obj->btf && btf__fd(obj->btf) >= 0) {
create_attr.btf_fd = btf__fd(obj->btf);
if (obj->btf && btf__fd(obj->btf) >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) {
load_attr.prog_btf_fd = btf__fd(obj->btf);
return obj->btf ? btf__fd(obj->btf) : -1;
create_attr.btf_fd = btf__fd(btf);
*fd_array = btf__fd(testmod_btf);