| Re: call_external with PASCAL calling convention [message #13033] |
Tue, 06 October 1998 00:00 |
rivers
Messages: 228
Registered: March 1991
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Senior Member |
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In article <3614D696.8B3EDE4C@mssl.ucl.ac.uk>, "E. Breeveld" <erb@mssl.ucl.ac.uk> writes:
> Any call_external gurus out there?
>
> We have a windows DLL that interfaces with a PC card and
> we'd like it to be incorporated (via call_external) into IDL, but
> can't make it work. The equivalent C program does work however!
> We are using IDL Version 5.1 Win32 (x86) with windows 98.
...
> The test idl program is:
>
> card = 0b ; Byte
> basadd2 = 0 ; Int
> irq1 = 0b ; Byte
> ; test without cdecl
> result = call_external('7200.dll', 'W_7200_Initial', $
> card, basadd2, irq1, val=[1, 0, 0])
> help, result, basadd2, irq1
> end
>
> The C program that works looks like:
>
> #include <windows.h>
> #include <stdio.h>
> #include "c:\7200\include\7200.h"
>
> unsigned char irq1;
> unsigned short base_address2;
> long status4;
>
> void main(void)
> {
> status4 = W_7200_Initial(0, &base_address2, &irq1);
> printf("Status= %ld\n"
> "Base Address= 0x%X\n"
> "IRQ= %d\n", status4, base_address2, irq1);
> }
...
> We could write a C wrapper for 7200.dll, but this is messy. Is there
> any other solution, or is there a bug in IDL with the /cdecl switch?
The problem here is clear: you cannot call this function W_7200_Initial
directly from IDL because it does not use the (argc, argv) argument passing
mechanism which IDL uses with CALL_EXTERNAL. You must write a wrapper routine
to convert IDL's (argc, argv) calling convention to the parameter list your
function needs.
____________________________________________________________
Mark Rivers (773) 702-2279 (office)
CARS (773) 702-9951 (secretary)
Univ. of Chicago (773) 702-5454 (FAX)
5640 S. Ellis Ave. (708) 922-0499 (home)
Chicago, IL 60637 rivers@cars.uchicago.edu (e-mail)
or:
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