Link external library with MSCV compiler

[JonB]

@elsa
I don't know in Qt Creator, but it can hardly be difficult, presumably you specify it at some point when you set up your project. Google for it.

Unless the error is from one of your libraries already being compiled 64-bit. Check whether those libraries with win32 in them are indeed 32-bit, not 64-bit.

Come on, you can do this, I can't answer!

[jsulm]

@elsa said in Link external library with MSCV compiler:

but then how do I change the target machine type?

Use Qt for that target machine type

[elsa]

@JonB @jsulm @mrjj I will try to start doing all the steps from scratch, because I am getting frustrated and cannot get on with the project because of this linker problem..
I am running Qt5.11.1. So what I read is that it only supports up to VS15, so I installed VS15. Qt, however, did not auto-detect the VS 14.0 compiler, so I had to add it manually. I found the path of the compiler .dll file but Qt also wants a make path (where is it?). This is where I am stuck now. Which make executable do I need for the compiler? and what else am I missing? I am sorry if my questions are to confusing or too easy. I am just trying to understand, because I never dealt with compilers and linkers in detail before and this problem came very unexpected.

[jsulm]

@elsa said in Link external library with MSCV compiler:

So what I read is that it only supports up to VS15

This is wrong - it supports VS17. But since VS15 and VS17 C++ compiler are compatible this does not matter. If you use Qt online installer you will see what compiler Qt 5.11.1 supports.

"but Qt also wants a make path" - can you please tell us exactly what it asks (screen-shot)?

If my understanding is correct the lib you want to use is built for x86, right? Official Qt build for Windows/VS are all x86_64. You will need a x86_64 build of that lib or build it by yourself.

[elsa]

@jsulm

This is a screenshot of the kit I am using now. This warning made me think that qt only supports VS15, but if it doesn't make a difference, then it's ok. This is now using the autodetected compiler (VS17), so I don't need to set up the path manually.
And yes the library is x86.

[jsulm]

@elsa OK, you have 32bit Qt, compiler and lib - does it work now?

[elsa]

@jsulm it produces this error:

f:\dd\vctools\crt\vcstartup\src\gs\gs_report.c:220: error: Debugger encountered an exception: Exception at 0xca9b99, code: 0xc0000409: , flags=0x1 (execution cannot be continued)
f:\dd\vctools\crt\vcstartup\src\gs\gs_report.c:220: error: Debugger encountered an exception: Exception at 0xca9b99, code: 0xc0000409: , flags=0x1 (execution cannot be continued)

[jsulm]

@elsa But this is when you try to run/debug the app, right?
Building it works?
To debug this error you should build in debug mode.

[elsa]

@jsulm oh true!! Sorry, I mixed it up. Yes, with the debugger it crashes at the end of one the functions.. I look into it more closely..

[elsa]

@jsulm
I commented some lines out to find the source of the problem and now it's producing the linking error again -.- This is the compile output:

	C:\Qt\Tools\QtCreator\bin\jom.exe -f Makefile.Debug
	link /NOLOGO /DYNAMICBASE /NXCOMPAT /DEBUG /SUBSYSTEM:WINDOWS "/MANIFESTDEPENDENCY:type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' publicKeyToken='6595b64144ccf1df' language='*' processorArchitecture='*'" /MANIFEST:embed /OUT:debug\DecaRangeRTLS.exe @C:\Users\FRHMELSA\AppData\Local\Temp\DecaRangeRTLS.exe.5688.156.jom
Qt53DExtrasd.lib(Qt53DExtrasd.dll) : fatal error LNK1112: module machine type 'x86' conflicts with target machine type 'x64'
jom: C:\Users\FRHMELSA\Documents\Projects\build-TREKdisplay-Desktop_Qt_5_11_1_MSVC2017_32bit-Debug\Makefile.Debug [debug\DecaRangeRTLS.exe] Error 1112
jom: C:\Users\FRHMELSA\Documents\Projects\build-TREKdisplay-Desktop_Qt_5_11_1_MSVC2017_32bit-Debug\Makefile [debug] Error 2
15:06:47: The process "C:\Qt\Tools\QtCreator\bin\jom.exe" exited with code 2.
Error while building/deploying project TREKdisplay (kit: Desktop Qt 5.11.1 MSVC2017 32bit)
The kit Desktop Qt 5.11.1 MSVC2017 32bit has configuration issues which might be the root cause for this problem.
When executing step "Make"

So the problem is with Qt3DExtras? Is this library 64bit? But this doesn't make sense right? Because whole Qt is 32bit and this is just part of it.

[jsulm]

@elsa Delete build folder, run qmake and build again.

[elsa]

This post is deleted!

[JonB]

@elsa

Qt53DExtrasd.lib(Qt53DExtrasd.dll) : fatal error LNK1112: module machine type 'x86' conflicts with target machine type 'x64'
So the problem is with Qt3DExtras? Is this library 64bit?

I read this the other way round. I have searched this error and MS docs state it's a "version mismatch" but nowhere clarify which is which in the error message... :(

I believe this is saying: Qt53DExtrasd is a module which is compiled x86 (32-bit), but your overall LINK is targetting x64 (64-bit).

If that's the case, somehow your makefile/compilation/link is still targetting 64-bit when you want it to target 32-bit.... Make 100% sure that whatever the qmake generates (a makefile?) has no references to 64-bit but only to 32-bit, and that everything (of yours) is rebuilt from scratch.

[elsa]

@jsulm @JonB thank you both a lot for your patience! The deleting of the build folder suggested by @jsulm did it. Now it builds fine, but I still cannot run it :( (see new thread). I will mark this question as solved as the linking is now successful.

[JonB]

@elsa Good. That's why we said you have to clean out completely if you change fundamental compilation, something will have been left over without doing that.

[elsa]

@JonB well, I thought it just creates a new build file for the new compiler (which it does), but I have to admit my understanding for compilers is not very deep.