How to convert QString to const char *
Is there any way to convert a QString to a const char * ?
You can do this:
- QString myString = "BlaBla"
- char* myChar = myString.toStdString().c_str();
Take care of the lifetime of these variables!
if you have an in parameter, you can do such things, although I would not got the way with std::string:
- void foo(const char*);
- QSTring text;
- QByteArray toAscii () const
- QByteArray toLatin1 () const
- QByteArray toLocal8Bit () const
It’s up to you, which encoding you use.
But all these functions return temporary objects, and calling constData returns the buffer of the temp objects. In the next line of code (when foo() returns) the temp object is destroyed and the buffer gets invalid!
Why should the be no way? I showed you some…
it is, but which format do you need?
- 7-bit ASCII?
- 8-bit ASCI with with regional code?
all are const char* formats.
QString is unicode.
in general, it is possible:
- QString text;
- std::string s = text.toLatin1().constData;
If you really need a const char* I would convert it to and std::string (but reagrd the conversion!) and use the std::string. Who shall otherwise handle the memory? who shall allocate it? who shall free it?
you can also do the following:
- QString text;
- chat* p = new char[text.length() + 1);
- strcpy(p, text.toLatin1().constData());
Take care that text.length() might not valid if you then convert to utf8!
i want to type cast QByteArray to a QString
now i have some data in myAppstring now i want it to convert in QString
so i have QString Constructor no 9 – which take const ByteArray
but it is now working
it give me error
is there any way to do conversion of Qbytearray to QString
QString Constructor No 9 (which takes a QByteArray) uses UTF-8, so you need to ensure that your byte array uses that encoding. It is better to use QString’s static methods fromLatin1, fromLocal8Bit and fromUtf8 IMO because they are more explicit.
You can check the documentation [qt-project.org] for more detailed explanation.
And I’d also like to recommend some good reading on character encoding [joelonsoftware.com] if you’re not already familiar with its concept.