It may produce a warning and continue processing or produce an error message and terminate. In both cases the message is sent to standard error. With the exception of error conditions encountered during the processing of the command line, the messages normally include the name and line number of the source file at the point the condition was encountered. Ipp was designed so that most exception conditions encountered will produce errors and terminate. This protects the user since warnings could simply be overlooked or misinterpreted.
Many ipp command require names as arguments.
Names must begin with a letter or an underscore, which may be followed by any number of letters, underscores, and digits. If any extraneous characters appear on a command line a warning is issued. This occurs when characters other than white-space or a comment follow the normal end of a command. The first form only allows simple textual substitution. Subsequent occurrences of name are replaced with text.