How to know when EnumWindows finishes its listing of windows?

How to know when EnumWindows finishes its listing of windows? Because EnumWindows receives a callback 开发者_Python百科function as parameter, and it keeps calling it until no more windows to be listed.

EnumWindows() blocks while enumeration is taking place. When EnumWindows() finishes enumerating through the windows, it returns a BOOL.

The following code snippet:

#include <windows.h>
#include <cstdio>

BOOL CALLBACK MyEnumWindowsProc(HWND hwnd, LPARAM lparam)
{
    int& i = *(reinterpret_cast<int*>(lparam));
    ++i;
    char title[256];
    ::GetWindowText(hwnd, title, sizeof(title));
    ::printf("Window #%d (%x): %s\n", i, hwnd, title);
    return TRUE;
}

int main()
{
    int i = 0;
    ::printf("Starting EnumWindows()\n");
    ::EnumWindows(&MyEnumWindowsProc, reinterpret_cast<LPARAM>(&i));
    ::printf("EnumWindows() ended\n");
    return 0;
}

gives me an output like this:

Starting EnumWindows()
Window #1 (<hwnd>): <title>
Window #2 (<hwnd>): <title>
Window #3 (<hwnd>): <title>
<and so on...>
EnumWindows() ended

So EnumWindows() definitely enumerates in a synchronous manner.