Difference between qrc:/ and :/

LScott

My understanding from reading the documentation is that 'qrc:/...' and ':/...' are basically equivalent? Is this correct, or am I misunderstanding?

If this is the case, why then does 'qrc:/...' work some places, and other places require ':/...' or it doesn't work?

SGaist

Hi,

AFAIK, qrc:// is the protocol specifier like ftp:// or http://. :/ is a shortcut.

Where did you saw the differences ?

LScott

@SGaist said in Difference between qrc:/ and :/:

AFAIK, qrc:// is the protocol specifier like ftp:// or http://. :/ is a shortcut.

So you mean :/ is a shortcut/alias for qrc:/?

It seems the main place this occurs is loading components from QML files in the resource system into C++:

QQmlApplicationEngine engine;
engine.load(QUrl("qrc:/MyComponent.qml")); //Loads fine.
engine.load(QUrl(":/MyComponent.qml"));      //File not found.

But the opposite seems true using 'qmlRegisterType':

qmlRegisterType("qrc:/MyComponent.qml", "my.uri", 1, 0, "MyComponent"); //'Warning: qmlRegisterType requires absolute URLs.
qmlRegisterType(':/MyComponent.qml", "my.uri", 1, 0, "MyComponent"); //This works just fine.

Investigating more, turns out using ":/MyComponent.qml", it seems to think it's a relative directory, so ends up resolving to "/home/lscott/qmlissue/build/debug/:/MyComponent.qml", when it should resolve to pretty much 'qrc:/MyComponent.qml".

In this case the file 'MyComponent.qml" is located at the root of the 'qml.qrc' file, which is added to the '.pro' with

RESOURCES += qml.qrc

FYI, this is in Linux (Debian 8.7) with Qt v5.9.2 for G++.

raven-worx

@LScott said in Difference between qrc:/ and :/:

So you mean :/ is a shortcut/alias for qrc:/?

yes both are the same. As @SGaist said qrc:/ is used where an url is expected and :/ where a file path is expected.

SGaist

Can you provide a minimal compilable example that shows that behaviour ?

timday

@LScott I'd be curious to know if it works any better if you use qrc:/// ? That form is certainly used in the Qt docs http://doc.qt.io/qt-5/resources.html which has an example

For example, the file path :/images/cut.png or the URL qrc:///images/cut.png would give access to the cut.png file"

BTW I think something was changed with resource URIs in 5.9.1 because I ran into an issue with some previously OK usage of qrc:// (note just two slashes) described here.