Message Parameter substitution produced an invalid string literal. Description In certain modes, the compiler will replace identifiers found within a string literal if they match a macro argument name. This form of "old-style stringization" is provided for compatibility with older C compilers. This message is output if this replacement forms an invalid string literal. User Action Modify the macro argument so that a valid string is formed. HP also recommends that the macro body be rewritten to use the standard C stringize operator (#).