20.3.1. Introduction

It is not uncommon for library developers to use one language to develop an application library that may be called by an application program written in a different language. MPI currently supports ISO (previously ANSI) C and Fortran bindings. It should be possible for applications in any of the supported languages to call MPI-related functions in another language.

Moreover, MPI allows the development of client-server code, with MPI communication used between a parallel client and a parallel server. It should be possible to code the server in one language and the clients in another language. To do so, communications should be possible between applications written in different languages.

There are several issues that need to be addressed in order to achieve interoperability.

Initialization:

We need to specify how the MPI environment is initialized for all languages.

Interlanguage passing of MPI opaque objects:

We need to specify how MPI object handles are passed between languages. We also need to specify what happens when an MPI object is accessed in one language, to retrieve information (e.g., attributes) set in another language.

Interlanguage communication:

We need to specify how messages sent in one language can be received in another language.