comp.lang.idl-pvwave archive - RDF feed
type: channel
description: Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
items: Re: call_external with PASCAL calling convention

Re: call_external with PASCAL calling convention
type: item
description: Oops - error in the Reply-to field of my last message, and no signature either. sorry. Eddie -- Edward Breeveld MSSL/UCL, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK e.breeveld@physics.org tel: +44 (0)1483 204178/267632 fax: +44 (0)1483 278312
creator: Eddie Breeveld
date: 1998-10-02T07:00:00-00:00

Re: call_external with PASCAL calling convention
type: item
description: 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: Argonne National Laboratory (630) 252-0422 (office) Building 434A (630) 252-0405 (lab) 9700 South Cass Avenue (630) 252-1713 (beamline) Argonne, IL 60439 (630) 252-0443 (FAX)
creator: rivers
date: 1998-10-06T07:00:00-00:00