[Libusb-devel] Some troubles with lib usb - thx for your help ;)

[<to...@fr...>]

Hi,
i'm using your lib and i have some problems :/
my entire code (very simple):

#include <iostream>
#include <iomanip>
#include <usbpp.h>

#define VENDOR_FTDI 0x0403
#define PRODUCT_FTDI 0x6001

using namespace std ;

int main(void)
{
    	struct usb_bus *busses ;
        struct usb_device *dev ;
    	struct usb_bus *bus ;

	// Initialisation de l'usb
    	usb_init() ; 			// Init de la classe
    	usb_find_busses() ;		// Scan de tous les bus
    	usb_find_devices() ;		// Scan de tous les périphériques
      	busses = usb_get_busses() ;	//

	// Pour tous les bus du système
	for (bus = busses ; bus ; bus = bus->next)
	{
		// Pour tous les périphériques connectés aux bus
    		for (dev = bus->devices ; dev ; dev = dev->next)
		{
			// Si le périphérique correspond au identifiants FTDI, effectuer le
traitement
    			if ((dev->descriptor.idVendor == VENDOR_FTDI)&&(dev->descriptor.idProduct
== PRODUCT_FTDI))
			{
				usb_dev_handle *handle ;

    				int ret;

				// Open
				handle = usb_open(dev) ;				cout << handle << endl ;

				ret = usb_claim_interface(handle,
dev->config->interface->altsetting->bInterfaceNumber);
				cout << "Claim " <<  ret << endl ;

   			  	char buf[6] = {0x1b, 0x11, 0x01, 0xcc, 0xf9, 0x1d} ;
				ret = usb_bulk_write(handle,
dev->config->interface->altsetting->endpoint->bEndpointAddress, buf,
sizeof(buf), 5000);
				cout << "Bulk " << ret << endl ;

				usb_close(handle) ;
    			}
    		}
    	}
	return EXIT_SUCCESS ;
}

My problem is that i can't claim the device and i've not find out why on the web
:/

When launching is have this :

[root@93-1ec101fa17f tests]# ./find_mice
0x605780  (comment : handle)
Claim -16 (comment : ret for claim)
Bulk -16  (etc..)

The error code seems to be -16 but i don't know him :/
I'm pretty new on programming on linux and i have some difficulties so maybe
i've forgot something really easy but i can't find out what :/

So thx for your time and help ;)
have a nice day