Hardware :: Accessing Device Driver From C Application

I wrote device driver to USB device, I can see it is alive and sending the data that I set it to send from the shell

Code:
cat /dev/myDev
How can I read from the device using C code?
I've tried to open it as a file and read it's content to buffer but noting returns..

Code:
char bufferin[500];
FILE* myDev = fopen("/dev/myDev", "r+");
size = fread(bufferin, 500, 500, myDev);