The RexxAddMacro return values are:
──────────────────────────────────────────────────────────────────────── 0 RXMACRO_OK The call to the function completed successfully. ────────────────────────────────────────────────────────────────────── 1 RXMACRO_NO_STORAGE There was not enough memory to complete the requested function. ────────────────────────────────────────────────────────────────────── 7 RXMACRO_SOURCE_NOT_FOUND The requested file was not found. ────────────────────────────────────────────────────────────────────── 8 RXMACRO_INVALID_POSITION An invalid search-order position request flag was used. ────────────────────────────────────────────────────────────────────────