We recommend that you implement each Motif widget in three files: a public header file, a private header file, and a source code file. If you call the new widget ExmMyName, Motif recommends that you call the public header file MyName.h, the private header file MyNameP.h, and the source code file MyName.c.
Some operating systems prohibit long filenames. If you are concerned with portability, abbreviate the filenames as described by the Intrinsics documentation.