Check whether selinux is enabled for (multi level securty) mls
#include <selinux/selinux.h>
int is_selinux_enabled();
int is_selinux_mls_enabled();
is_selinux_enabled() returns 1 if SELinux is running or 0 if it is not. On error, -1 is returned.
is_selinux_mls_enabled() returns 1 if SELinux is running in MLS mode or 0 if it is not.