Unsolved QSettings issue mingw32 vs. msvc

[Enrico]

Hi,
Could someone please give me a hint on why I get access error when writing to a key in the registry, but only when my application is build with msvc (2013, havent tried others)
If the application is build with mingw32 everything works as expected.
The framework is the prebuild versions. 5.5.1 and 5.7.0

[mrjj]

hi
Thats pretty odd!
both exe is named the same etc?

Could VS make a manifest file that changes something and mingw will not?

[Enrico]

Hi,
Actually have only tried compiling in debug mode and runned in debugmode from QtCreator.

But I guess it will give same result in release mode.

I discovered the issue when building a DLL which should be able to access the same key. (That DLL is build with msvc)
I then tryed building the other application with msvc, and found same issue.

[mrjj]

@Enrico
it possible to reproduce with small sample?
Could be bug :)

[Enrico]

Made a simple sample, you can get i here www.daniac.dk/QSettingsTest.zip

Exact same issue here, might be a bug

[mrjj]

@Enrico
hi
i tried mingw on win 10. no messages. ( as expected)

then i tried
windows 7, visual studio 2013 , 32 bit
and no messages also?

both Qt 5.5.1/ 5.7

let me try 5.7 in VS.
and see if it makes any difference.

[Enrico]

Sorry but when you say no messages.

The only messages is from qDebug()

Have changed the sample to show the results in a plaintext box - Sorry

[mrjj]

@Enrico
oh, i expected some window dialog to pop up saying access denied :)

so what is the sign of error im looking for ?

[Enrico]

I have modified and updated the sample with a plaintextedit showwing the results - Sorry

mingw32 - Output:
Getting MyNewPort value:COM2
Setting MyNewPort=COM2 status:0 <- Success
Getting MyNewPort value:COM2

msvc - Output:
Getting MyNewPort value:default <- Failed reading also
Setting MyNewPort=COM2 status:1 <- Failed writing
Getting MyNewPort value:default <- Failed reading also

[mrjj]

@Enrico
hi
sorry for the delay

win 7, vs 2013 , Qt 5.7

I get
Getting MyNewPort value:default
Setting MyNewPort=COM2 status:1
Getting MyNewPort value:default

so failed. ( thx @VRonin )

mingw
Getting MyNewPort value:COM2
Setting MyNewPort=COM2 status:0
Getting MyNewPort value:COM2

[VRonin]

@mrjj status: 1 = fail

[mrjj]

@VRonin
thx. need more coffee :)
so sample did fail :)

Can anyone else try the sample with VS compiler
and say if they get same result before we call it a bug :)

[VRonin]

MSVC2013 win 7 Qt 5.5.1 and 5.7.0 both 32 and 64 bit versions all failing

[Enrico]

I have filed a bug
https://bugreports.qt.io/browse/QTBUG-55257