Adapt a program to a new version of Qt

LorsDavos

I have a program that works on Qt 5.13.2, and I need to migrate it to 5.14.2.

On Linux, both versions work without modifying my code, but on Windows, version 5.14.2 does not run. Here's the error message displayed:
"The procedure entry point _ZN20QtextStreamFunctions4endlER11QtextStream could not be located in the dynamic link library."

LorsDavos

It's alright, I've solved it. The executable on Windows was using Qt 5.13.2 DLL files, all I had to do was to update them.

Pl45m4

@LorsDavos said in Adapt a program to a new version of Qt:

Qt 5.13.2, and I need to migrate it to 5.14.2.

What's the point updating to 5.14.2 and not to the lastest Qt 5 LTS release (which is 5.15)?!

On Linux, both versions work without modifying my code, but on Windows, version 5.14.2 does not run

It's more likely an error how Qt is linked to your program

Axel Spoerl

@LorsDavos
As @Pl45m4 said, you should consider updating to a Qt version with a longer perspective, while at it. Recommend 6.2 or better 6.5.

Just by looking at the error message: Check your code for a stream operator<<, streaming the endl macro. This pattern will likely hit you with an upgrade to any higher version. Try replacing it by \n.

ChrisW67

@LorsDavos said in Adapt a program to a new version of Qt:

"The procedure entry point _ZN20QtextStreamFunctions4endlER11QtextStream could not be located in the dynamic link library."

http://demangler.com/ tells me the affected function is QtextStreamFunctions::endl(QtextStream&) which triggered @Axel-Spoerl's comment.
There's no Qt class called QtextStream. Perhaps you have not copy-pasted the error message or you have a consistent typo in your code.

LorsDavos

The context is that I received a Qt 5.13.2 program and I need to install a plugin. However, this plugin works in Qt 5.14.2. I wish not to stray too far in version to avoid making too many changes. I don't think the problem lies in the code because I compiled it under both versions of Qt on Linux without any modifications, and both executables work perfectly. When I switch to Windows, both compile fine; however, when I run version 5.14.2, it gives me this error _ZN20QtextStreamFunctions4endlER11QtextStream.
I searched, and in the directory C:\Qt\Qt5.14.2\5.14.2\mingw73_64\include\QtCore, I found these files "QTextStream, qtextstream.h, QTextStreamFunction, and QTextStreamManipulator".

JonB

@LorsDavos
I don't know why.where this is happening, but the problem is the capitalization in the error message:
_ZN20QtextStreamFunctions4endlER11QtextStream
This has QtextStream but it really should be QTextStream (upper-case T), e.g. as per https://stackoverflow.com/questions/62559840/how-to-solve-the-no-qt-platform-plugin-could-be-initialized-problem

The procedure entry point ?endl@QTextStreamFunctions@@YAAEAVQTextStream@@AEAV2@@Z could not be located in the dynamic link library C:\Qt\5.14.1\msvc2017_64\bin\Qt5WebChannel.dll.

So far as I know case-difference is significant in all linkers, so I wonder why it is looking for QtextStream... anything.

LorsDavos

It's alright, I've solved it. The executable on Windows was using Qt 5.13.2 DLL files, all I had to do was to update them.