Bug in "Async Find window and set window title"

[somanuell]

The sample titled "Async Find window and set window title" in README.md contains the code:

const buf = Buffer.alloc(title.length * 2)
u32.GetWindowTextW.async(hWnd, buf, buf.byteLength, err3 => {

But the Win32 API GetWindowTextW wants a character count as third parameter, not a byte count. In unicode a character is two bytes.

So the code should be (imho):

const buf = Buffer.alloc(title.length * 2)
u32.GetWindowTextW.async(hWnd, buf, title.length, err3 => {

[somanuell]

By passing buf.byteLength, you tell the API that you have allocated a buffer twice as big as you really did. If title.length is actually the real length of the text, the API will write an extra binary zero beyond the allocated space. Some 32 bits versions of node.exe do not care, that's for sure. But if you greatly underestimate title.length, then node.exe will just crash! No crash is possible if you always pass the allocated size / 2...

[waitingsong]

got it

[waitingsong]

fixed