Modern C++ Programming Cookbook

How to do it...

To create a string from an identifier using the preprocessor's operator#, use the following pattern:

1. Define a helper macro taking one argument that expands to # followed by the argument:

        #define MAKE_STR2(x) #x 

2. Define the macro you want to use, taking one argument that expands to the helper macro:

        #define MAKE_STR(x) MAKE_STR2(x)

To concatenate identifiers together using the preprocessor's operator##, use the following pattern:

1. Define a helper macro with one or more arguments that use the token-pasting operator ## to concatenate arguments:

        #define MERGE2(x, y)    x##y

2. Define the macro you want to use, by using the helper macro:

        #define MERGE(x, y)     MERGE2(x, y)