winapi - How to identify inside screen resolution the multiple display that is enabled? -

i've searched on google found no answer, if knows thankful!

i want use command line or winapi check state of multiple display. example : if set : "extended screen" or "duplicate screen" want able verify it. have no idea start.

thanks lot

i start winapi enumdisplaymonitors function: http://msdn.microsoft.com/en-us/library/dd162610%28vs.85%29.aspx

bool enumdisplaymonitors(   _in_  hdc hdc,   _in_  lpcrect lprcclip,   _in_  monitorenumproc lpfnenum,   _in_  lparam dwdata ); 

you need call function setting first 2 parameters null this:

enumdisplaymonitors(null, null, mypaintenumproc, 0);  //enumerates display monitors. //the callback function receives null hdc. 

now have monitorenumproc callback function: http://msdn.microsoft.com/en-us/library/dd145061%28v=vs.85%29.aspx

bool callback monitorenumproc(   _in_  hmonitor hmonitor,   _in_  hdc hdcmonitor,   _in_  lprect lprcmonitor,   _in_  lparam dwdata ); 

you wiil filled lprcmonitor back:

a pointer rect structure. if hdcmonitor non-null, rectangle intersection of clipping area of device context identified hdcmonitor , display monitor rectangle. rectangle coordinates device-context coordinates.

if hdcmonitor null, rectangle display monitor rectangle. rectangle coordinates virtual-screen coordinates. 

based on values monitors can decide whether have extended mode (the rects different) or duplicate (they equal).

hth - luck!