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This code is an example for using libUSB to deal with USB devices and controllering them without writing kernel modules.
It is usefull if you want to control homemade usb devices or if you want to write a driver for unsupported usb device in your OS.
The following example searches for any USB mouse attached to your system , removes the kernel driver , opens the device and keeps polling it for bytes and prints them.

#include < iostream >
#include < cstdlib >
#include < stdio.h >
#include < string.h >
#include < usb.h >
#include < usbpp.h >

#define DEBUG_LEVEL 0

#define PROTOCOL_MOUSE 2
#define PROTOCOL_KEYBOARD 1

using namespace std;

struct usb_bus *busses,*bus,*dbus;

int findDevice(int PROTOCOL,struct usb_device *device){
bool found=false;
struct usb_device *dev;

usb_find_busses();
usb_find_devices();
busses=usb_get_busses();
for (bus=busses;bus && !found;bus=bus->next){
for (dev=bus->devices;dev;dev=dev->next){
if (dev->config->interface->altsetting->bInterfaceProtocol==PROTOCOL) {dbus=bus;found=true;break;}
}//end of devices loop
}//end of busses loop
if (!found) return -1;
*device=*dev;
return 1;
}

int main(int argc, char *argv[])
{
struct usb_device *dev;
char *buf;
int n,x,r;
char string[50];
bool found=false;
usb_dev_handle *fdev;
usb_set_debug(DEBUG_LEVEL);
usb_init(); //initilize the usb library

if (findDevice(PROTOCOL_MOUSE,dev)<0){ //search for a USB mouse , you can change it to keyboard,joystick…etc
printf(”Unable to find the required device !nexsitingn”);
exit(1);
}

printf(”Now we are dealing with device from vendor ID : %d (%x) n”,dev->descriptor.idVendor,dev->descriptor.idVendor);
printf(”Trying to open the device…n”);
if (fdev=usb_open(dev)) printf(”Device opened successfully.n”); //Here we open the device , just like fopen
else { printf(”Operation failed :-(n”); exit(1);}

buf=(char*)calloc(1,100);
if (usb_get_driver_np(fdev,0,buf,100)) printf(”Kernel Using Driver : %sn”,buf); //Trying to get the kernel driver name (optional)
else printf(”Could not read the driver name :-(n”);

if (usb_detach_kernel_driver_np(fdev,0)) printf(”Device detached successfully from the kernel.n”); //detach the driver from the kernel , seems to be just like rmmod , but it always returns errors , however , it wroks
else printf(”Error detaching the device :-(n”);

if (r=usb_claim_interface(fdev,0)) printf(”Interface Claimed !!n”); //reserving the device interface for our applicatoin , if another driver/software is using the device , it will return ‘interface busy’
printf(”Interface Claim Status : %dn”,r);

printf(”Device Protocol : %dn”,dev->descriptor.bDeviceProtocol);
printf(”Report Length : %dn”,dev->descriptor.bLength);
printf(”Decriptor Type : %dn”,dev->descriptor.bDescriptorType);
printf(”End Points : %dn”,dev->config->interface->altsetting->bNumEndpoints);
printf(”Interface Class : %dn”,dev->config->interface->altsetting->bInterfaceClass);
printf(”Protocol : %dn”,dev->config->interface->altsetting->bInterfaceProtocol);
printf(”Interface Number: %dn”,dev->config->interface->altsetting->bInterfaceNumber);
printf(”Device Filename : %sn”,dev->filename);
printf(”Bus Dir Name : %sn”,dbus->dirname);

usb_get_string_simple(fdev,dev->descriptor.iManufacturer,string,sizeof(string));
printf(”Device Manfucaturer : %sn”,string);
usb_get_string_simple(fdev,dev->descriptor.iProduct,string,sizeof(string));
printf(”Product Name : %sn”,string);
usb_get_string_simple(fdev,dev->descriptor.iSerialNumber,string,sizeof(string));
printf(”Device Serial Number: %sn”,string);
printf(”End point addresses : 0x%xn”,dev->config->interface->altsetting->endpoint->bEndpointAddress);

while (string[0]!=3){
string[0]=string[1]=string[2]=string[3]=0;
r=usb_interrupt_read(fdev,0×81,string,4,0); //I am reading 4 bytes using interrupt read , note that not every usb device supports interrupt read/write
for (x=0;x<4 && r>0;x++)
printf(”%d “,string[x]);
printf(”n”);
usb_clear_halt(fdev,0×81); I need to reset the device node because of some devices (usually keyboards) keep sending the same bytes even after releasing the key !
}

printf(”Closing Device.n”);
usb_release_interface(fdev,0);
usb_close(fdev);

return EXIT_SUCCESS;
}
To compile this code , you need usblib and the library headers.
The output of this program will be 4 numbers
x1 x2 x3 x4