void MyFrame::OnMouseUp(wxMouseEvent& event) { if (event.ButtonIsDown(wxMOUSE_BTN_LEFT)) { std::cout << "Left mouse button released." << std::endl; } }In this example, we define a function called "OnMouseUp" which takes a wxMouseEvent as a parameter. We check if the left mouse button is down using the "ButtonIsDown" function, and if it is, we print a message to the console. This code would typically be part of a wxWidgets application written in C++, and would use the wxWidgets library to handle GUI and input events like mouse clicks.