| Re: How to send a CHARACTER to a C/C++/FORTRAN function via CALL_EXTERNAL? [message #83241] |
Thu, 14 February 2013 01:25 |
Lajos Foldy
Messages: 176
Registered: December 2011
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Senior Member |
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On Thursday, February 14, 2013 6:08:24 AM UTC+1, Bogdanovist wrote:
> On Thursday, 14 February 2013 05:44:34 UTC+11, Brian J. Daniel wrote:
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>> A character is one byte. You could try the byte data type defined with the appropriate ASCII value.
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>> On Tuesday, February 12, 2013 8:36:16 PM UTC-5, Bogdanovist wrote:
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>>> I'm having trouble getting a CALL_EXTERNAL call to work. I think the issue is the requirement to send a CHARACTER*1. To be specific, I'm trying to call dgels from LAPACK, see here
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>>> http://www.netlib.org/lapack/explore-html/d7/d3b/group__doub le_g_esolve.html#ga225c8efde208eaf246882df48e590eac
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>>> I know from previous experience that you have to be careful to get all arguments to CALL_EXTERNAL exactly right, making IDL INTs into LONGs, making sure to get single/double precision etc correct. However this one I can't seem to crack. It doesn't surprise me that the IDL STRING is not equivalent to CHARACTER, but how can I send this correctly?
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> Thanks! I've tried using:
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> trans='N'
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> c_trans=BYTE(N[0])
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> but my IDL session still dies when I send this to the routine. There may be other problems with the other arguments though. Do you know if BYTE() will assign the correct ASCII Byte code or do I need to look that up and assign it directly (numerically)?
Fortran arguments are passed by reference, try an IDL byte array: BYTE('N').
regards,
Lajos
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| Re: How to send a CHARACTER to a C/C++/FORTRAN function via CALL_EXTERNAL? [message #83242 is a reply to message #83241] |
Wed, 13 February 2013 21:08  |
Matt Francis
Messages: 94
Registered: May 2010
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Member |
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On Thursday, 14 February 2013 05:44:34 UTC+11, Brian J. Daniel wrote:
> A character is one byte. You could try the byte data type defined with the appropriate ASCII value.
>
>
>
> On Tuesday, February 12, 2013 8:36:16 PM UTC-5, Bogdanovist wrote:
>
>> I'm having trouble getting a CALL_EXTERNAL call to work. I think the issue is the requirement to send a CHARACTER*1. To be specific, I'm trying to call dgels from LAPACK, see here
>
>>
>
>>
>
>>
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>> http://www.netlib.org/lapack/explore-html/d7/d3b/group__doub le_g_esolve.html#ga225c8efde208eaf246882df48e590eac
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>> I know from previous experience that you have to be careful to get all arguments to CALL_EXTERNAL exactly right, making IDL INTs into LONGs, making sure to get single/double precision etc correct. However this one I can't seem to crack. It doesn't surprise me that the IDL STRING is not equivalent to CHARACTER, but how can I send this correctly?
Thanks! I've tried using:
trans='N'
c_trans=BYTE(N[0])
but my IDL session still dies when I send this to the routine. There may be other problems with the other arguments though. Do you know if BYTE() will assign the correct ASCII Byte code or do I need to look that up and assign it directly (numerically)?
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