遇到syscall.Syscall和WinAPI的麻烦

Question

I'm trying to use VkKeyScan from the Window's API, however the program crashes whenever that function is called. I've had no problems with other Window's API functions I've imported and used in this way. Is there something wrong with my syscall.Syscall call?

var (
    user32, _ = syscall.LoadLibrary("user32.dll")
    vkKeyScan, _ = syscall.GetProcAddress(user32, "VkKeyScan")
)

func VkKeyScan(char byte) (int16, syscall.Errno) {
    var nargs uintptr = 1
    ret, _, callErr := syscall.Syscall(uintptr(vkKeyScan), nargs, uintptr(char), 0, 0)
    return int16(ret), callErr
}

Answer 1

VkScanKey works in C because it’s #defined roughly like this:

#ifdef UNICODE
#   define VkScanKey VkScanKeyW
#else
#   define VkScanKey VkScanKeyA
#endif

So VkScanKey isn’t the real symbol—VkScanKeyW is, and that’s the only form GetProcAddress will take it in. If you had been doing proper error handling you might have noticed that GetProcAddress was failing rather than Syscall, which might have tipped you off to this fact.