Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!warper.jhuapl.edu From: gotwols@warper.jhuapl.edu (Bruce Gotwols) Newsgroups: comp.lang.idl-pvwave Subject: RE: Summary to: A Provocative Question Message-ID: <6108@aplcen.apl.jhu.edu> Date: 28 Jul 90 03:12:12 GMT Sender: news@aplcen.apl.jhu.edu Reply-To: gotwols@warper.jhuapl.edu (Bruce Gotwols) Organization: JHU-Applied Physics Laboratory Lines: 33 Nntp-Posting-Host: warper.jhuapl.edu In a recent posting, Ralph Finch writes that he has found a reason to pay the extra $1200. for PV WAVE rather than buying IDL from RSI: > I did find something which for us is worth the price difference, > namely, the capability of calling IDL/Wave from Fortran. For others > your mileage may vary. Sorry, but I disagree with his conclusion. In IDL version 1 you can call Fortran or C or any other language supported on the VAX two different ways: 1. by the so called mailbox, and 2, by the LINKIMAGE mechanism. The LINKIMAGE mechanism is fast but a bit cumbersome to set up for a beginner. Nevertheless it is used here a lot (don't ask me for the details.). the Mailbox scheme works too but is slower and should be considered to be obselete. In version 2 of (VAX only) IDL a new scheme was made available which is practically trivial once you see an example. It has the name CALL_VMS and allows routines written in other languages to be called without having to do a lot of system mumbo jumbo. Linkimage is also available in Version 2, but the obsolete mailbox scheme mentioned above has been eleminated. I routinely call routines written in both C and Fortran in both versions 1 and 2 of VAX IDL. Someone even wrote a series of routines that call the National Instruments GPIB (IEEE-488) routines so we could do real time data acquistion from within the IDL environment! So apparently BOTH IDL and PV-WAVE provide hooks to allow C or Fortran routines to be called. Unfortunately this is currently not the case for SUN IDL. -- -- Bruce L. Gotwols Johns Hopkins University, Applied Physics Lab., Laurel MD 20723 Internet: gotwols@warper.jhuapl.edu (128.244.176.48)