If you must use macros, give them unique names

Reason

Macros do not obey scope rules.

Example

#define MYCHAR        /* BAD, will eventually clash with someone else's MYCHAR*/

#define ZCORP_CHAR    /* Still evil, but less likely to clash */

Note

Avoid macros if you can: ES.30, ES.31, and ES.32. However, there are billions of lines of code littered with macros and a long tradition for using and overusing macros. If you are forced to use macros, use long names and supposedly unique prefixes (e.g., your organization's name) to lower the likelihood of a clash.

Enforcement

Warn against short macro names.