Allowed variable names in C

The following types of names have various problems:

Names beginning with an underscore

Names beginning with two underscores, like __var, or an underscore and a capital letter, _Var, are reserved for system use.

Prefixes you can't use

str, mem

Suffixes you can't use

_t

Reserved by Posix.

E<digit>

Reserved for error codes.

Web links

• What are the rules about using an underscore in a C++ identifier?
• C Reserved Identifiers

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