[SOLVED] Failed to load platform plugin.

soroush · wrote on 4 Jan 2013, 09:42

I have compiled Qt5 libraries for Windows using MinGW. Programs compiled with that version doesn't run on 64 bit Windows. AFAIK it should be possible to run a 32bit application on 64bit machine. The error seems something related to msvcrt.dll :

!http://s1.picofile.com/file/7607928167/x86_qt5_error.png(test)!

For 64-bit versions, there is no problem. This is the simple "test GUI test":http://s3.picofile.com/file/7607874836/Q.7z.html program containing all DLLs needed to run (including msvcrt.dll)

koahnig · wrote on 4 Jan 2013, 09:58

You can run 32 bit applications on 64 bit windows. I am running minGW compiled 32 bit applications on Windows 7 64 bit.

Did you check the required dlls with the dependency walker already?

soroush · wrote on 4 Jan 2013, 11:11

[quote author="koahnig" date="1357293503"]
Did you check the required dlls with the dependency walker already? [/quote]

Yes. Everything looks sane to me. I double-echecked PATH, architectures of binaries, and everything else. Can't find the problem...

Program exits with following error message:
@
Failed to load platform plugin "windows". Available platforms are:

Invalid parameter passed to C runtime function.
Invalid parameter passed to C runtime function.
@

lgeyer · wrote on 4 Jan 2013, 11:26

Did you deploy platform/qwindows.dll as well? (It will not show up in Dependency Walker).

soroush · wrote on 4 Jan 2013, 11:54

[quote author="Lukas Geyer" date="1357298812"]Did you deploy platform/qwindows.dll as well? (It will not show up in Dependency Walker).[/quote]

No I didn't know about that. It's not present in installation directory. It's in qtbase/plugin/platform. Though adding that file, program does not run yet.

I made a 7z archive of all DLL s that Dependency Walker can see + msvcrt . It just don't run on any 64bit windows machine. I had no chance to test with 32 yet

lgeyer · wrote on 4 Jan 2013, 12:07

It is actually platform s /qwindows.dll, not platform/qwindows.dll. Be aware that you will have to deploy platforms/qwindows d .dll if you are deploying a debug build.

With these changes, do you still get <code>Failed to load platform plugin "windows". Available platforms are:</code>?

soroush · wrote on 4 Jan 2013, 12:38

[quote author="Lukas Geyer" date="1357301238"]It is actually platform s /qwindows.dll, not platform/qwindows.dll.[/quote]

Yea, my typo

[quote author="Lukas Geyer" date="1357301238"]Be aware that you will have to deploy platforms/qwindows d .dll if you are deploying a debug build.

With these changes, do you still get <code>Failed to load platform plugin "windows". Available platforms are:</code>?[/quote]

I tried both debug and release builds with libraries with/without debugging symbols. It's still same.

lgeyer · wrote on 4 Jan 2013, 13:15

Using the <code>-platformpluginpath</code> command line option or the <code>QT_QPA_PLATFORM_PLUGIN_PATH</code> environment variable might be another option, but Qt should pickup the plugin automatically when placed in the correct location.

soroush · wrote on 4 Jan 2013, 14:24

[quote author="Lukas Geyer" date="1357305345"]Using the <code>-platformpluginpath</code> command line option or the <code>QT_QPA_PLATFORM_PLUGIN_PATH</code> environment variable might be another option, but Qt should pickup the plugin automatically when placed in the correct location.[/quote]

It is there, I copied everything beside the program executable. I believe it's in visible scope for linkage. The problem might be related to msvcrt .

Chris Kawa · 6 Sept 2015, 17:21

qwindows.dll shouldn't be in the same dir as the executable. Put it in the platforms subdirectory.

soroush · wrote on 4 Jan 2013, 14:54

[quote author="Krzysztof Kawa" date="1357310438"]qwindows.dll shouldn't be in the same dir as the executable. Put it in the platforms subdirectory.[/quote]
Ah my bad memory :P In fact I have had same problem with paths for mysql driver on windows... Now works fine.

Thank you

MuldeR · wrote on 4 Jan 2013, 20:36

[quote author="Lukas Geyer" date="1357298812"]Did you deploy platform/qwindows.dll as well? (It will not show up in Dependency Walker).[/quote]

FWIW: DLL's that are loaded at runtime, like Plug-in DLL's, do show up in Dependency Walker, but only when you use the "profiling" feature. They of course cannot be found by only analyzing the static import tables...

lgeyer · wrote on 6 Jan 2013, 12:14

Profiling never worked quite well for me (STATUS_STACK_BUFFER_OVERRUN and alike), but good to know. Thanks for sharing.

ThomasAn · wrote on 6 Feb 2013, 22:00

Can you elaborate how this issue was fixed ?
You created a "platforms" directory inside your project folder and put the qwindows.dll in there ?

Shuhard · wrote on 5 Mar 2013, 16:11

Looks like you have to create "platforms" directory in folder, were your program runs. For example, I have "debug" folder in my project, and I copied "platforms" directory there from "c:\Qt\Qt5.0.1\5.0.1\mingw47_32\plugins". This solved my problem.

Also you can copy other plugins if needed.

welmore · wrote on 6 Sept 2015, 17:21

@Chris-Kawa

Hi. I did as you said and it worked! thanks!
welmore