__noop
The Microsoft-specific __noop intrinsic specifies that a function should be ignored. The argument list is parsed, but no code is generated for the arguments. The compiler considers the arguments as referenced for the purposes of compiler warning C4100 and similar analysis. The __noop intrinsic is intended for use in global debug functions that take a variable number of arguments.
The compiler converts the __noop intrinsic to 0 at compile time.
Example
The following code shows how you could use __noop.
// compiler_intrinsics__noop.cpp
// compile using: cl /EHsc /W4 compiler_intrinsics__noop.cpp
// compile with or without /DDEBUG
#include <stdio.h>
#if DEBUG
#define PRINT printf_s
#else
#define PRINT __noop
#endif
#define IGNORE(x) { __noop(x); }
int main(int argv, char ** argc)
{
IGNORE(argv);
IGNORE(argc);
PRINT("\nDEBUG is defined\n");
}