[Development] Question about QCoreApplicationData::*_libpaths

Thiago Macieira thiago.macieira at intel.com
Wed Jan 20 22:37:50 CET 2016

On Wednesday 20 January 2016 22:25:27 Kevin Kofler wrote:
> And Qt also has a real 
> pop unlike the misleadingly-named STL one: takeLast/takeFirst.

In the Standard Library's defence: the pop() function does not return the 
element due to exception-safety. Example:

    value_type takeLast() { value_type v = last(); remove(size() - 1); return 
v; }

The copy constructor is called once, then the move constructor. If 
value_type's move constructor is not noexcept, then it may throw after the 
container resized.

You could add this overload to solve it:

	void pop(value_type &where) { where = back(); pop(); }

But then your code looks like:

	Element e;		// may throw, allocate resources, etc.

instead of:

	Element e = v.back();	// move-constructed

Also note that this overload would keep the integrity of the container, but 
not necessarily your data.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center

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