@Juraj taht was my own code and it don't work.
@pert yes the message was wrong... but I don't even get it...
if I define something outside the header, and check for it with ifdef, I get nothing... :
as far as I can understand, the compiler doesn't if the define is or will be call, so it don't work...
in my example, all I get is:
#error "No or invalid network selected"