- eval '*F_GETFL = sub { 0 };';
- eval '*F_SETFL = sub { 0 };';
- eval '*IPPROTO_TCP = sub { 6 };';
- eval '*TCP_NODELAY = sub { 1 };';
+ eval '*F_GETFL = sub { 0 };' unless defined *F_GETFL;
+ eval '*F_SETFL = sub { 0 };' unless defined *F_SETFL;
+ eval '*IPPROTO_TCP = sub { 6 };' unless defined *IPPROTO_TCP;
+ eval '*TCP_NODELAY = sub { 1 };' unless defined *TCP_NODELAY;