Macros reference

The macros that are listed in Compiler predefined macros have compiler-predefined values. These predefined macros are used to conditionally compile code for specific compilers, specific versions of compilers, specific environments, and specific language features. Some predefined macros are protected, which means that the compiler will issue a warning message if you try to undefine or redefine them. Some predefined macros are unprotected and can be undefined or redefined without warning.

The compiler also provides many other macros that you can use in your programs. For example, XL C/C++ supports function-like macros with a variable number of arguments, as a language extension for compatibility with C and as part of C++11. The Other macros section lists some of the compiler-supplied macros that do not have predefined values.