Calling C Code from IDL Modules

David Fanning has some excellent advice and useful info about calling C from IDL.

Tips

(From David Fanning):

  • All arrays which need to be passed between IDL and C must be allocated in IDL. This includes both arrays being passed from IDL to C and from C back to IDL. Sometimes this requires an initial call to the C code to return the array sizes which IDL will allocate, if the array sizes are not known to IDL beforehand.
  • Don't deallocate any arrays which were passed from IDL.
  • Don't pass strings, rather pass byte arrays. It is much simpler. Convert strings to byte arrays in IDL before or after the Call_External call.
  • Convert all output variables to the data type which C is expecting in the Call_External call.

Links

Examples

-- ElizabethAuden - 11 May 2005

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Topic revision: r1 - 2005-05-11 - ElizabethAuden
 
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