I’m attempting to utilize the GetAsyncKeyState function in Assembly language to detect the state of a keyboard key. Specifically, I want to print a message when the user presses the “W” key. However, I encountered an “undefined symbol” error when attempting to use the GetAsyncKeyState function.

I’ve ensured that I’ve correctly included the user32.lib library file, and I’m using the correct function name in my code. I even tried manually adding extern GetAsyncKeyState: PROC to declare the GetAsyncKeyState function, but the issue persists.

INCLUDE Irvine32.inc
INCLUDELIB user32.lib

.data
    message db "user32.lib is working!", 0
    msg db "You pressed 'W'", 0
.code
main proc
    invoke MessageBoxA, 0, ADDR message, ADDR caption, MB_OK
    call CheckForKey
main endp

CheckForKey PROC
    mov eax, 'W'
    call GetAsyncKeyState
    test eax, eax
    jz notPressed

    mov edx, OFFSET msg
    call WriteString
    jmp endCheck

notPressed:
    jmp endCheck

endCheck:
    ret
CheckForKey ENDP


end main

I want to test if I can print a string when I press ‘W’ using GetAsyncKeyState, but I encountered this error when using GetAsyncKeyState.I’m wondering what might be causing this error and how to resolve it. Any assistance would be greatly appreciated!