Screen 1

Sub WaitMouse Alias "WaitMouse" (button As String) Export
    Dim but As Byte
    Dim res As Integer
    Dim buttons As Integer
    Dim x As Integer
    Dim y As Integer
    If button = "L" Or button = "R" Or button = "M" Or button = "A" Then
  Do
   res = GetMouse(x,y,,buttons)
   If res = 0 Then ' если функция отработала нормально
    Select Case button
     Case "A"
      If buttons And 1 Then but = 1
      If buttons And 2 Then but = 1
      If buttons And 4 Then but = 1
     Case "R"
      If buttons And 2 Then but = 1
     Case "M"
      If buttons And 4 Then but = 1
     Case "L"
      If buttons And 1 Then but = 1
    End Select
   EndIf
  Loop Until but = 1
    Else
  Print "Error, you must use 'R', 'L', 'M', or 'A' as argument in WaitMouse()"
    End If
End Sub

WaitMouse("R")
? "OK"
sleep

int fb_GfxGetMouse(int *x, int *y, int *z, int *buttons, int *clip)
{
    int failure = TRUE;
    int temp_z, temp_buttons, temp_clip;

    FB_GRAPHICS_LOCK( );

    if (!z)
  z = &temp_z;
    if (!buttons)
  buttons = &temp_buttons;
    if (!clip)
  clip = &temp_clip;
    if ((__fb_gfx) && (__fb_gfx->driver->get_mouse)) {
  DRIVER_LOCK();
  failure = __fb_gfx->driver->get_mouse(x, y, z, buttons, clip);
  DRIVER_UNLOCK();
    }

    FB_GRAPHICS_UNLOCK( );

    if (failure) {
  *x = *y = *z = *buttons = *clip = -1;
  return fb_ErrorSetNum(FB_RTERROR_ILLEGALFUNCTIONCALL);
    }
    return fb_ErrorSetNum( FB_RTERROR_OK );
}

if (failure) {
  *x = *y = *z = *buttons = *clip = -1;
  return fb_ErrorSetNum(FB_RTERROR_ILLEGALFUNCTIONCALL);
    }

If buttons And 1 Then but = 1
      If buttons And 2 Then but = 1
      If buttons And 4 Then but = 1