range checking in GPC

Dear GPC-ers, Upon including a range checking directive in the program program test1; {$R+} const nmax = 6; type nrange = 1..nmax; var n : nrange; begin read(n); writeln(n); end. and compiling with gpc --borland-pascal test1.p the compiler answers: test1.p:2: warning: unknown compiler directive `r+' My questions: (i) In the gpc manual on p. I read ... "all of BP compiler directives are supported by GPC..." {$R+} is one of them. Why the reaction above? (ii) is there any possibility of range checking with GPC? I could not find the expression "range checking" in the manual text. Thanks in advance, K. Veselic.