Duplicate symbol:DOS

questions
1

I have a small application in C10 that I need to compile as an exe in “lib” mode (That means that all the dependent dlls get linked in; correct??) and when I compile I get the following errors…

Duplicate symbol: @VMT@DOS_FileDriverEH in DOSPON.OBJ, DOSPON.OBJ
Duplicate symbol: Dos$DrvReg in DOSPON.OBJ, DOSPON.OBJ
Duplicate symbol: DOS_FileDriverEH$Run@F in DOSPON.OBJ, DOSPON.OBJ

The conditional compilation symbols are…

STRINGTHEORY=>0;
NETTALKLOG=>1;
ODDJOB=>0;
CRYPTONITE=>0;
StringTheoryLinkMode=>1;
StringTheoryDllMode=>0;
MD5=>0;_
ABCDllMode_=>0;
ABCLinkMode=>1;
NetTalkDllMode=>0;
NetTalkLinkMode=>1

Can anyone please suggest how to fix this?

2

I wonder if you have the DOS driver in the .CwProj more than once
which I would expect the GUI would normally prevent
Can you post your .CwProj ?

3

Thanks Mark, I had a look at the .cwproj and it looked OK.

I then deleted all the source code (.clw and /obj) and regenerated everything and now it compiled OK. I suspect it needed a clean out?

Err, except I forgot that I had reset the compile to .dll DOH!

4

OK, I’m pretty sure it is IQXML that is causing the issue, I can’t compile the IQXML example apps in Lib mode because it generates a “Missing IQXMLL.Lib” error. I have a copy of IQXMLL.Lib, from somewhere?? and if I add that I get the duplicate symbols error.

Does anyone have a IQXMLL.Lib file that works in Lib mode?

5

not really. Let’s back up a step;

(when supported) there are fundamentally two “libraries” in play;
a) a DLL along with a small stub LIB. (like say CLADOS.DLL and CLADOS.LIB)
b) a bigger LIB which contains all the code (like say CLADOSL.LIB)

So, it’s not really correct to say that the “dependant dll’s get linked in”. In LIB mode they’re not used at all. It just links in CLADOSL.LIB . And CLADOSL.LIB and CLADOS.DLL are different files. LIB mode links in the former. It ignores the latter. DLL mode links in the stub (CLADOS.LIB). The linker never sees the DLL. (That’s loaded at runtime.)

Earlier I said “when supported”. This duplication, creating both a DLL and a LIB for of some code is very much optional. Most “outside clarion” DLL’s do not have a matching LIB, and so LIB mode just links in the stub LIB (or the program loads the DLL at runtime). So, for example, you can use OpenSSL DLL’s in a Lib-mode program, but you still need to ship the DLLs.

LIB mode is “harder” to make, because in LIB mode “everything is exported”. In DLL’s, the DLL has control over what is exported. The Linker never actually sees the DLL (just the stub LIB) so there’s not much room for confusion.

The problem is a LIB mode LIB, which includes “some other part” - like in this case the iqXML (allegedly) is using the DOS file driver, and so is linking CLADOSL “inside” it. This becomes a problem if you also use the CLADOSL lib because now the linker has the same thing twice, and can’t tell them apart. It means the iqXML LIB (in this example) has to be careful not to include the driver - trusting the parent app (ie your app) to supply that later. (This is somewhat harder than it looks, and you can get into trouble if versions are not kept in sync.)

Another option is for your solution to not include the DOS file driver. That’s also difficult because the drivers are added to the projects by the template so that gets complicated and is usually not a practical solution.

In short - Local (LIB) mode Exes are complicated to build. All the moving parts need to be done right, and there’s then a lot of trust (between the pieces) involved. It’s easy for things to go wrong when the app gets more complicated.

In your case it’s not like you’ll end up with one EXE anyway. StringTheory and NetTalk for example both load DLL’s at runtime (ZLIB, OpenSSL etc) regardless of whether the app is in DLL mode or LIB mode. So I’m not sure how far down the rabbit hole you want to go.

6

Thanks Bruce, that makes me feel less ignorant. :grinning_face_with_smiling_eyes: I remember the good 'ol days when linking in local mode was easy; it might have been the only option back then!

The rabbit hole is already pretty deep, this is a C10 app/exe that is called by a C6 multi dll app and if I try to ship everything in the same folder I get mismatched dlls and for historical reasons shipping everything in the one folder is the preferred option. Maybe I’m doomed to failure.

I’ll have a quick look at the IQXML templates to see if they also include the DOS driver.

7

I had a play around with the templates and got the example IQXML template app to compile, but not my more detailed app which also includes an old version of Nettalk and StringTheory.

I’ve got no idea where I got my copy of IQXMLL.lib from, it’s not included in the IQXML install. There are instructions at the IQXML Github repository for how to deal with duplicate symbols …

…but I couldn’t figure them out?

For the time being I am installing my C10 app in a separate folder to the C6 app and it seems to be working OK.