Passing to a console application (managed via QProcess) UTF-8 encoded parameters

[Chicken Blood Machine]

exiflist_params << QString::fromLocal8Bit(fileName);

exiflist_params << QString::fromLocal8Bit(fileName);

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[Conel]

Nop, this is not the case

fileName variable is a QString (not a ByteArray), i.e. fileName is Unicode (not a Local8Bit encoded)

The problem is that fileName QString is converted by QProcess to QByteArray (== char*)(as I suppose with using toLocal8Bit() method) and then passed it to the console application. But I'd like fileName to be converted to UTF-8

[Chicken Blood Machine]

Did you try QString::toUtf8() ?

[Conel]

I thought about

exiflist_params << fileName.toUtf8();

exiflist_params << fileName.toUtf8();

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but this is wrong since fileName.toUtf8() gives QByteArray which will be used for creating QString (costructor QString::QString ( const QByteArray & ba )) which will be inserted into exiflist_params. This cunstructror constructs QString assuming that QByteArray contains ASCII encoded data. This I think just like

exiflist_params << QString::fromAscii(fileName.toUtf8());

exiflist_params << QString::fromAscii(fileName.toUtf8());

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It seems to be weird and does not work

[Bitto]

On Mac OS X, QProcess uses UTF-8 for command line arguments. On Windows and Unix, it calls QString::toLocal8Bit(). If your file system uses UTF-8, just make sure your applications run the UTF-8 locale too (a good idea, in general). So fex, export LANG=en_US.UTF-8, and then launch your app. QProcess will then use UTF-8 for the arguments.

[frankiefrank]

I'm having the same issue - trying to write a German umlaut (ü) to QProcess but it doesn't work.

toLatin1() gets me "?", toUtf8() and toLocal8Bit() get me random symbols.

I didn't manage to understand from this thread how to address this. I'm running on Windows 7. Is there a way to set QProcess to handle UTF-8?

[yeye_olive]

I do not think there is a way to change QProcess' behaviour, which unfortunately abstracts arguments as Unicode strings instead of plain NULL-terminated byte sequences. Here are two suggestions for working around the problem, in unspecified order of ugliness:

1. Call QTextCodec::​setCodecForLocale() to set an UTF-8 codec, so that when QProcess calls QString::toLocal8Bit() to serialize the arguments, UTF-8 will be used. Unfortunately, this means changing an application-wide setting to solve a local issue.
2. Preprocess the arguments before adding them to the QProcess' argument list: QString::fromLocal8Bit(fileName.toUtf8()). Something may get lost in translation.

[frankiefrank]

Thank you for your reply!

After some thinking I figured I really could skip the whole cmd.exe usage and do something else. But I hope this thread is helpful to other users.