get complete type

[allozano]

I need get the param type. For example
void f (std::string){...}

with Macros TYPE_NAME, TYPE_DECL,... i find the param is "string" but  I 
need "std::string" for code generator.

I dont find the fields or macros in the files tree.h and cp/cp-tree.h 
and don find information in google.

Thanks and sorry for my english