sockets - Linux. SOL_NETLINK not defined -

i trying use sol_netlink in setsockopt in linux, , got error saying sol_netlink not defined although in included socket.h file.

googled answers , saw people redefine sol_netlink in own files due "linux header file confusion".

any explanation that?

i compile-checked code on raspbian pi, , compiles without warnings.

#include <sys/socket.h> #include <stdio.h>  int main(int argc, char *argv[]) {         printf ("sol_socket=%d\n", sol_socket);         return 0; }