how to check if webcam is used by another application

hi, i am using webcamtexture to access webcam from webplayer but if another application or website is using webcam then my game crashes how can i check if another application is using webcam. i can check if webcam is attached to system or not by using WebcamTexture.devices but how can i check if WebcamTexture.devices[0] is not used by another application

Regards