我看过这篇关于使用的文章std::variant https://en.cppreference.com/w/cpp/utility/variant。这是因为以下代码引发了代码分析警告:
void CChristianLifeMinistryHtmlView::OnTimer(UINT_PTR nIDEvent)
{
if (nIDEvent == ID_TIMER_ZOOM)
{
//get the zoom value
VARIANT vZoom{};
vZoom.vt = VT_I4;
vZoom.lVal = 0;
ExecWB(OLECMDID_OPTICAL_ZOOM, OLECMDEXECOPT_DONTPROMPTUSER, nullptr, &vZoom);
TRACE("zoom %d\n", vZoom.lVal);
//kill the timer
KillTimer(nIDEvent);
GetParent()->PostMessage(UWM_HTMLVIEW_CHANGE_ZOOM_MSG, vZoom.lVal);
return;
}
CHtmlView::OnTimer(nIDEvent);
}
警告:
Warning C26476 https://learn.microsoft.com/en-us/cpp/code-quality/c26476?view=msvc-160:表达/符号{{0, 0, 0, 0, {0}}}
使用带有多个类型指针的裸联合“union”:使用variant
相反(类型7)。
我开始尝试更改代码:
void CChristianLifeMinistryHtmlView::OnTimer(UINT_PTR nIDEvent)
{
if (nIDEvent == ID_TIMER_ZOOM)
{
//get the zoom value
std::variant<long> vZoom(0);
ExecWB(OLECMDID_OPTICAL_ZOOM, OLECMDEXECOPT_DONTPROMPTUSER, nullptr, &vZoom);
TRACE("zoom %d\n", vZoom.lVal);
//kill the timer
KillTimer(nIDEvent);
GetParent()->PostMessage(UWM_HTMLVIEW_CHANGE_ZOOM_MSG, vZoom.lVal);
return;
}
CHtmlView::OnTimer(nIDEvent);
}
但问题是ExecWB
期望一个VARIANT *
我不知道如何通过这个std::variant
.