23.3 Identifiers

Implementation-Defined Behavior for Identifiers is covered in section G.3.3 of the ANSI C Standard.

How many characters beyond thirty-one (31) are significant in an identifier without external linkage? (ISO 6.1.2)

All characters are significant.

How many characters beyond six (6) are significant in an identifier with external linkage? (ISO 6.1.2)

All characters are significant.

Is case significant in an identifier with external linkage? (ISO 6.1.2)

Yes.