connect(camera, static_cast<void(QCamera::*)(QCamera::LockStatus, QCamera::LockChangeReason)>(&QCamera::lockStatusChanged),
[=](QCamera::LockStatus status, QCamera::LockChangeReason reason){ /* ... */ });
static_cast<void(QCamera::*)(QCamera::LockStatus, QCamera::LockChangeReason)>(&QCamera::lockStatusChanged)
上面這句是一個靜態轉換 static_cast<>()
QCamera::* 是類指針
QCamera::LockStatus 函數參數
QCamera::LockChangeReason 函數參數
&QCamera::lockStatusChanged 函數地址