% cat icpc-macro-issue.cc template <typename T> struct Foo { }; /* Icpc chokes when expanding this macro when T is a template type: T is substituted with no additional surrounding space, generating a token `>>'. G++ has no such problem, but I haven't checked which is the right behavior, required by the ISO standard. Note that this will no longer be a problem with C++ 0x, since expressions like `Foo<Foo<int>>' will be valid. */ #define foo(T) Foo<T> int main () { foo(Foo<int>) f; } % icpc -gcc-name=gcc-4.0 -o icpc-macro-issue icpc-macro-issue.cc icpc-macro-issue.cc(20): error: space required between adjacent ">" delimiters of nested template argument lists (">>" is the right shift operator) foo(Foo<int>) f; ^ compilation aborted for icpc-macro-issue.cc (code 2) % g++ -o icpc-macro-issue icpc-macro-issue.cc %