Clang extern "C" parse error

Hello everyone. I'm using CompilerInstance and CompilerInvokation.
I'm trying to parse a simple file:
//-------------
extern "C" {
}
//-----------
And i got a error: expected identifier or '('. What i'm doing wrong? Why
clang can't parse blocks 'extern "C"' and 'extern "C++"'?
P.S. I have set a langOpts.CPlusPlus to 1;