Question

I have a method that has this signature

void SetFoo(QString& foo);

and I’m trying to pass an empty string inline, but none of the following compile

SetFoo("");
SetFoo(QString(""));

(error: no matching function for call to ‘MyClass::SetFoo(QString)’)

but if I create a variable like this, it works.

QString emptyFoo = "";
SetFoo(emptyFoo);

Is there not a way to call the method without creating a variable explicitly?

NOTE:
Everything seem to work in windows environment with using vc++ compiler but I encounter the above mentioned compilation error in linux environment using g++.

Answer 1

You can create a global object as a const QString nullStr() and use it everywhere- Somewhat similar to Null Object Pattern.

Alternatively as billz mentions, a const reference to a temporary can exist, so making it const Qstring& will enable the first 2 versions

Regardless, you should change the reference to const Qstring& if you dont intend to modify it.