ANSI C - identifiers naming rule

通常static變數/函數, 我都會以_var, _func為命名方式, 也符合C99 7.1.3標準,

7.1.3 Reserved identifiers

Each header declares or defines all identifiers listed in its associated subclause, and optionally declares or defines identifiers listed in its associated future library directions subclause and identifiers which are always reserved either for any use or for use as file scope identifiers.
-- All identifiers that begin with an underscore and either an uppercase letter or another underscore are always reserved for any use.
-- All identifiers that begin with an underscore are always reserved for use as identifiers with file scope in both the ordinary and tag name spaces.