X3J3/96-134 Date: August 12, 1996 To: X3J3 From: Jerrold Wagener Subject: TR-C Subgroup Report Reference: WG5-N1214 ISO/IEC JTC1/SC22/WG5/N1214 25-Jul-96 To: WG5 From: WG5/Interop Subject: TR-C subgroup report References: WG5/N1178(X3J3/96-069), WG5/N1185(X3J3/96-119), X3J3/96-106r1, X3J3/95-295. At the Dresden meeting, WG5/Interop investigated most of the outstanding technical issues of the interoperability report N1178, as well as the option to include a MAP_TO conversion facility into the TR. As a result of this work, the following conclusions can be made: (1) /Interop recommends to add a MAP_TO facility for automatic conversion of the type and/or kind of data objects of basic types, along the lines of X3J3/95-295. This would enhance the current facilities (KIND parameters for C datatypes) and diminuish the current divergence of the ISO and HPFF interoperability approaches. (2) /Interop thinks that regardless of the type mapping mechanism for structure components (KINDs or MAP_TO), there is a need for a layout clause like BIND(C) inside the TYPE definition for a C struct. (3) /Interop recommends that C character strings be mapped to Fortran CHARACTER(LEN=1) arrays as proposed in X3J3/96-106r1. (4) /Interop feels that a , which only establishes a new name for an existing type, does not have significant impact on other features of the language. It is aware of the fact that the current is not able to model ALL possible C typedef constructs, but only those with a well-defined meaning in Fortran. (5) Interfacing to operating system facilities is often dependent on the possibility to access global variables defined in these interfaces. Therefore, /Interop would like to express the necessity to provide a binding to C extern data objetcs. (6) /Interop concurs with the issues raised in N1185 about MAP_TO and struct mappings. Therefore, it does not recommend a "recursive mapto". Nevertheless, the TR-C development body is encouraged to investigate alternative possibilities to specify MAP_TO conversion, e.g. at the specification of structure components.