What are Multicharacter Literals in C and C and Are They Considered Bad Style?

Multicharacter Literals in C and C

Multicharacter literals are character constants that contain more than one character. In C and C , these literals are of type int, regardless of the characters they contain. For example, the following code defines an enum using multicharacter literals:

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

The C99 standard states that the value of a multicharacter literal is implementation-defined, meaning that its interpretation may vary depending on the compiler and platform. This can be problematic for platform-independent serialization, as the value of a multicharacter literal may not be interpreted consistently across different platforms.

Uses of Multicharacter Literals

Despite their potential drawbacks, multicharacter literals can be useful in certain situations. One common use case is for debugging purposes. By using multicharacter literals, it can be easier to identify specific values in a memory dump. For example:

enum state { waiting, running, stopped };

vs.

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

In a memory dump, the multicharacter literals would be more easily recognizable than the plain integer values:

00 00 00 02 . . . .

vs.

73 74 6F 70 s t o p

Are Multicharacter Literals Considered Bad Style?

The use of multicharacter literals in C is primarily for compatibility with C code. In general, it is considered better practice to use single-character literals or string literals when appropriate. However, multicharacter literals can still be useful in certain situations, such as when debugging or when performing platform-specific optimizations.

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