Prevent Windows taskbar still being visible when applications are in fullscreen.

main.c

#include <stdio.h>
#include <stdlib.h>

#include <windows.h>

int main()
{
	HWND hwnd = FindWindow("Shell_TrayWnd", NULL);
	if (hwnd == NULL) {
		fprintf(stderr, "Unable to find the taskbar.\n");
		return EXIT_FAILURE;
	}

	SetWindowPos(hwnd, HWND_NOTOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE);

	return EXIT_SUCCESS;
}