The normal rules for RPG IV symbolic names apply; reserved words cannot be used (see Symbolic Names). The name can begin in any position in the space provided. Thus, indenting can be used to indicate the shape of data in data structures.
For continued name lines, a name is specified in positions 7 through 80 of the continued name lines and positions 7 through 21 of the main definition line. As with the traditional definition of names, case of the characters is not significant.
For an externally described subfield, a name specified here replaces the external-subfield name specified on the EXTFLD keyword.
For a prototype parameter definition, the name entry is optional. If a name is specified, the name is ignored. (A prototype parameter is a definition specification with blanks in positions 24-25 that follows a PR specification or another prototype parameter definition.)
If you are defining a prototype and the name specified in positions 7-21 cannot serve as the external name of the procedure, use the EXTPROC keyword to specify the valid external name. For example, the external name may be required to be in lower case, because you are defining a prototype for a procedure written in ILE C.