Multicharacter literal in C and C++

Question

I didn't know that C and C++ allow multicharacter literal: not 'c' (of type int in C and char in C++), but 'tralivali' (of type int!)

enum
{
    ActionLeft = 'left',
    ActionRight = 'right',
    ActionForward = 'forward',
    ActionBackward = 'backward'
};

Standard says:

C99 6.4.4.4p10: "The value of an integer character constant containing more than one character (e.g., 'ab'), or containing a character or escape sequence that does not map to a single-byte execution character, is implementation-defined."

I found they are widely used in C4 engine. But I suppose they are not safe when we are talking about platform-independend serialization. Thay can be confusing also because look like strings. So what is multicharacter literal's scope of usage, are they useful for something? Are they in C++ just for compatibility with C code? Are they considered to be a bad feature as goto operator or not?

Answer 1

It makes it easier to pick out values in a memory dump.

Example:

enum state { waiting, running, stopped };

vs.

enum state { waiting = 'wait', running = 'run.', stopped = 'stop' };

a memory dump after the following statement:

s = stopped;

might look like:

00 00 00 02 . . . .

in the first case, vs:

73 74 6F 70 s t o p

using multicharacter literals. (of course whether it says 'stop' or 'pots' depends on byte ordering)