Because someone in our group hates exceptions (let's not discuss that here), we tend to use error-checking macros in our C++ projects. I have encountered an odd compilation failure when using a templated function with two type parameters. There are a few errors (below), but I think the root cause is a warning: warning C4002: too many actual parameters for macro 'BOOL_CHECK_BOOL_RETURN' Probably best explained in code: #include "stdafx.h" template<class A, class B> bool DoubleTemplated(B & value) { return true; } template<class A> bool SingleTemplated(A & value) { return true; } bool NotTemplated(bool & value) { return true; } #define BOOL_CHECK_BOOL_RETURN(expr) \ do \ { \ bool __b = (expr); \ if (!__b) \ { \ return false; \ } \ } while (false) \ bool call() { bool thing = true; // BOOL_CHECK_BOOL_RETURN(DoubleTemplated<int, bool>(thing)); // Above line doesn't compile. BOOL_CHECK_BOOL_RETURN((DoubleTemplated<int, bool>(thing))); // Above line compiles just fine. bool temp = DoubleTemplated<int, bool>(thing); // Above line compiles just fine. BOOL_CHECK_BOOL_RETURN(SingleTemplated<bool>(thing)); BOOL_CHECK_BOOL_RETURN(NotTemplated(thing)); return true; } int _tmain(int argc, _TCHAR* argv[]) { call(); return 0; } Here are the errors, when the offending line is not commented out: 1>------ Build started: Project: test, Configuration: Debug Win32 ------ 1>Compiling... 1>test.cpp 1>c:\junk\temp\test\test\test.cpp(38) : warning C4002: too many actual parameters for macro 'BOOL_CHECK_BOOL_RETURN' 1>c:\junk\temp\test\test\test.cpp(38) : error C2143: syntax error : missing ',' before ')' 1>c:\junk\temp\test\test\test.cpp(38) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(41) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(48) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(49) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(52) : error C2143: syntax error : missing ';' before '}' 1>c:\junk\temp\test\test\test.cpp(54) : error C2065: 'argv' : undeclared identifier 1>c:\junk\temp\test\test\test.cpp(54) : error C2059: syntax error : ']' 1>c:\junk\temp\test\test\test.cpp(55) : error C2143: syntax error : missing ';' before '{' 1>c:\junk\temp\test\test\test.cpp(58) : error C2143: syntax error : missing ';' before '}' 1>c:\junk\temp\test\test\test.cpp(60) : error C2143: syntax error : missing ';' before '}' 1>c:\junk\temp\test\test\test.cpp(60) : fatal error C1004: unexpected end-of-file found 1>Build log was saved at "file://c:\junk\temp\test\test\Debug\BuildLog.htm" 1>test - 12 error(s), 1 warning(s) ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Any ideas? Thanks!