Info Catalog
m4: Syntax
m4: Quoted strings
3.1 Macro names
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A name is any sequence of letters, digits, and the character '_'
(underscore), where the first character is not a digit. 'm4' will use
the longest such sequence found in the input. If a name has a macro
definition, it will be subject to macro expansion (⇒Macros).
Names are case-sensitive.
Examples of legal names are: 'foo', '_tmp', and 'name01'.