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April 26th, 2018, 05:12 AM
#1
Alt key virtual codes
Inspecting the `Right Alt` key messages using `Microsoft Spy++` returns the following:
Code:
WM_KEYDOWN nVirtKey:VK_CONTROL
WM_KEYDOWN nVirtKey:VK_MENU
WM_SYSKEYUP nVirtKey:VK_CONTROL
WM_KEYUP nVirtKey:VK_MENU
Why does the key generate 2 messages `VK_CONTROL` and `VK_MENU`? Why is the type of `VK_CONTROL` SYS (system) while `VK_MENU` non-system?
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April 28th, 2018, 07:29 AM
#2
Re: Alt key virtual codes
WM_SYSKEYUP is sent when a system key is released (a system key is one when the ALT key is already pressed). WM_KEYUP is sent when a non-system key is released (ALT key is not also pressed). Similar for WM_SYSKEYDOWN and WM_KEYDOWN.
VK_MENU is the ALT key. VK_CONTROL is the CTRL key. So you're pressed the CTRl key, then the ALT key (so WM_KEYDOWN rather than WM_SYSKEYDOWN as ALT is not already pressed), then released the CTRL key (WM_SYSKEYUP as ALT is pressed) then released the ALT key.
See https://msdn.microsoft.com/en-us/lib...(v=vs.85).aspx
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C++23 Compiler: Microsoft VS2022 (17.6.5)
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