Qt and frequency of a display?

[spherrra]

How do you know the frequency of a monitor (display) programmatically by Qt? Thank you!

[spherrra]

Is it really by Qt, or I can use Win API, Linux API and etc?

[wysota]

You can use whatever API you want.

[spherrra]

You can use whatever API you want.
I did not understand what you mean. For cross-platform software should I use all the API for all operating systems.

[wysota]

So use appropriate APIs on each of the operating systems you want to support. Qt doesn't have own API for detecting frequencies of displays.