QString to Unicode to char*

[Daxos]

Hi all,
I want to be able to convert my QString in unicode format and the convert it in char*.

I have try with the following code but I have a casting problem (my QByteArray contains only the first character).

QByteArray xByteArray((const char *)qsTmp.unicode(), qsTmp.size()*2);

QByteArray xByteArray((const char *)qsTmp.unicode(), qsTmp.size()*2);

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Any Suggestions?

with regards, Dax

[tbscope]

Let's see:

The QString class provides a Unicode character string

That's already taken care of.

Now, to turn it into a char pointer:

QString myString("Hello world");
 
char *myStringChars = myString.toUtf8().data();

QString myString("Hello world");

char *myStringChars = myString.toUtf8().data();

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[Daxos]

Thankyou tbscope,
are you sure that this code work correctly? My debugger (VS2005) show me bad characters in myStringChars but I don't know if is a format-code problem.

[tbscope]

You mean you actually have a unicode string?
Yes, that's correct.

Understand what a unicode string is.

[ChrisW67]

Now, to turn it into a char pointer:

QString myString("Hello world");
char *myStringChars = myString.toUtf8().data();

QString myString("Hello world");
char *myStringChars = myString.toUtf8().data();

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That's likely to end in tears. QString::toUtf8() returns a temporary QByteArray, data() returns a pointer to its data buffer, and then the temporary QByteArray ceases to exist. Ultimately, you get a char* to a buffer inside a temporary object that no longer exists and can therefore be overwritten by other machine processes.

You need to control the scope of the QByteArray:

QByteArray ba = myString.toUtf8();
char *myStringChars = ba.data();
// do stuff with myStringChars
// let ba go out of scope

QByteArray ba = myString.toUtf8();
char *myStringChars = ba.data();
// do stuff with myStringChars
// let ba go out of scope

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[tbscope]

Yes, now I remember it :-)
I knew there was something wrong with it.

[Daxos]

Ok, thanks

[sysmaniac]

Consider using the qPrintable macro.