bpf_link_get_fd_by_id
err = bpf_link_get_fd_by_id(&attr);
fd = bpf_link_get_fd_by_id(id);
fd = bpf_link_get_fd_by_id(id);
fd = bpf_link_get_fd_by_id(id);
LIBBPF_API int bpf_link_get_fd_by_id(__u32 id);
evsel->bperf_leader_link_fd = bpf_link_get_fd_by_id(entry->link_id);
evsel->bperf_leader_link_fd = bpf_link_get_fd_by_id(entry.link_id);
link_fd = bpf_link_get_fd_by_id(next_id);
err = bpf_link_get_fd_by_id(0);
ASSERT_EQ(bpf_link_get_fd_by_id(link_info.id), -EPERM, "link_get_fd_by_id_fails");