To:		WG5

From:		Jamie Shiers

Subject:	Draft NP for TR2 on Interoperability with C



Title:  Interoperability between Fortran and C



Scope:  Permit Fortran procedures to call C procedures



Purpose and Justification:  A technical report of type 2 is being produced to define

the specific extensions to Fortran that will permit Fortran procedures to call C

procedures.  It is intended that these extensions will be included in a future

revision of the Fortran standard exactly as specified in the report, unless

problems are encountered by early implementation of these extensions.  The

purpose of producing this report is to enable compiler vendors to meet the

demand for this requirement in a more timely manner than would be possible if

they were to wait for the next revision of the Fortran standard.



A significant fraction of the standard (de-facto or de-jure) computing

environment comes with a C API.  Examples include X-windows libraries, Motif,

TCP/IP socket calls and interfaces to system routines.  The Fortran programmer is

currently unable to exploit this wealth of software in a portable manner.  This

causes many problems for those who, for example, wish to front-end a powerful

scientific visualisation package, written in Fortran, with a sophisticated graphical

user interface (GUI).  Due to the difficulties of providing such an interface in a

standard fashion, many users are turning to alternative languages for such

applications, even if Fortran is ideally suited to the "computational" component

of the task.



It is therefore very important that a standard mechanism by which C procedures

can be called from Fortran procedures is defined as soon as possible.



Implementation schedule:  The most pressing problem is to establish a work-

group and a Project Editor.  This should be done by May 1995.  Once such a work-

group has been established, an NP and initial WD could be produced by the end

of June, drawing from material that has already been submitted to WG5. 

Assuming that the proposals contained in these documents are largely acceptable,

it should be possible to reach PDTR stage by the November WG5 meeting or the

end of the year.