| Re: CALL_EXTERNAL - Fortran Troubles [message #5335 is a reply to message #5333] |
Wed, 08 November 1995 00:00  |
rivers
Messages: 228
Registered: March 1991
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Senior Member |
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In article <309FE62C.F46@cdc.noaa.gov>, Jim Brown <jtb@cdc.noaa.gov> writes:
> Hello all:
>
> Please forgive me if somebody else has posed a similar question, but
> I am stumped! I have obtained some code from a colleague that makes
> use of the CALL_EXTERNAL function to execute Fortran code. I have
> been able to understand hs example and make certain routines work, but
> I have hit a dead end.
>
> Now I can get the above code (and other code for that matter) to work if I
> am only passing back arrays containing REALS. What I would like to do is
> to have a routine pass back both reals and a string such as the following
> shows:
> Note, the only change was the addition of the string variable, units.
> Everything compiles great, but I cannot get the value of the variable
> named units passed back into my IDL routine.
You need to provide some more information:
- What product are you using (IDL or PV-WAVE). They pass parameters
differently to CALL_EXTERNAL
- What operating system are you using, VMS, UNIX, Windows, etc.
IDL's CALL_EXTERNAL passes parameters differently with Unix and VMS.
IDL passes STRINGS by descriptor, i.e. the address of a structure
containing the length and address of the string. You are not allowed to
change the length of the string in your routine. You can get around this
by converting to BYTE before calling your FORTRAN routine.
____________________________________________________________
Mark Rivers (312) 702-2279 (office)
CARS (312) 702-9951 (secretary)
Univ. of Chicago (312) 702-5454 (FAX)
5640 S. Ellis Ave. (708) 922-0499 (home)
Chicago, IL 60637 rivers@cars3.uchicago.edu (Internet)
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