NAME

       Device::USB - Use libusb to access USB devices.

VERSION

       Version 0.36

SYNOPSIS

       Device::USB provides a Perl wrapper around the libusb library. This supports Perl code controlling and
       accessing USB devices.

           use Device::USB;

           my $usb = Device::USB->new();
           my $dev = $usb->find_device( $VENDOR, $PRODUCT );

           printf "Device: %04X:%04X\n", $dev->idVendor(), $dev->idProduct();
           $dev->open();
           print "Manufactured by ", $dev->manufacturer(), "\n",
                 " Product: ", $dev->product(), "\n";

           $dev->set_configuration( $CFG );
           $dev->control_msg( @params );
           ...

       See the libusb manual for more information about most of the methods. The functionality is generally the
       same as the libusb function whose name is the method name prepended with "usb_".

DESCRIPTION

       This module provides a Perl interface to the C library libusb. This library supports a relatively full
       set of functionality to access a USB device. In addition to the libusb, functioality, Device::USB
       provides a few convenience features that are intended to produce a more Perl-ish interface.

       These features include:

       •   Using the library initializes it, no need to call the underlying usb_init function.

       •   Object interface reduces namespace pollution and provides a better interface to the library.

       •   The find_device method finds the device associated with a vendor id and product id and creates an
           appropriate Device::USB::Device object to manipulate the USB device.

       •   Object interfaces to the bus and device data structures allowing read access to information about
           each.

Device::USB

       This class provides an interface to the non-bus and non-device specific functions of the libusb library.
       In particular, it provides interfaces to find busses and devices. It also provides convenience methods
       that simplify some of the tasks above.

   CONSTANTS
       This class provides a set of constants for the defined device classes. The constants defined at this time
       are:

       •   CLASS_PER_INSTANCE

       •   CLASS_AUDIO

       •   CLASS_COMM

       •   CLASS_HID

       •   CLASS_PRINTER

       •   CLASS_MASS_STORAGE

       •   CLASS_HUB

       •   CLASS_DATA

       •   CLASS_VENDOR_SPEC

   FUNCTIONS
       new Create a new Device::USB object for accessing the library.

       debug_mode
           This class method enables low-level debugging messages from the library interface code.

           level
               0 disables debugging, 1 enables some debug messages, and 2 enables verbose debug messages

               Any other values are forced to the nearest endpoint.

       find_busses
           Returns the number of changes since previous call to the function: the number of busses added or
           removed.

       find_devices
           Returns the number of changes since previous call to the function: the number of devices added or
           removed. Should be called after find_busses.

       find_device
           Find a particular USB device based on the vendor and product ids. If more than one device has the
           same product id from the same vendor, the first one found is returned.

           vendor
               the vendor id

           product
               product id for that vendor

           returns a device reference or undef if none was found.

       find_device_if
           Find a particular USB device based on the supplied predicate coderef. If more than one device would
           satisfy the predicate, the first one found is returned.

           pred
               the predicate used to select a device

           returns a device reference or undef if none was found.

       list_devices
           Find all devices matching a vendor id and optional product id. If called with no parameters, returns
           a list of all devices. If no product id is given, returns all devices found with the supplied vendor
           id. If a product id is given, returns all devices matching both the vendor id and product id.

           vendor
               the optional vendor id

           product
               optional product id for that vendor

           returns a list of devices matching the supplied criteria or a reference to that array in scalar
           context

       list_devices_if
           This method provides a more flexible interface for finding devices. It takes a single coderef
           parameter that is used to test each discovered device. If the coderef returns a true value, the
           device is returned in the list of matching devices, otherwise it is not.

           pred
               coderef to test devices.

           For example,

               my @devices = $usb->list_devices_if(
                   sub { Device::USB::CLASS_HUB == $_->bDeviceClass() }
               );

           Returns all USB hubs found. The device to test is available to the coderef in the $_ variable for
           simplicity.

       list_busses
           Return the complete list of information after finding busses and devices.

           By using this function, you do not need to do the find_* calls yourself.

           returns a reference to an array of busses.

       get_busses
           Return the complete list of information after finding busses and devices.

           Before calling this function, remember to call find_busses and find_devices.

           returns a reference to an array of busses.

DIAGNOSTICS

       This is an explanation of the diagnostic and error messages this module can generate.

DEPENDENCIES

       This module depends on the Carp, Inline and Inline::C modules, as well as the strict and warnings
       pragmas. Obviously, libusb must be available since that is the entire reason for the module's existence.

AUTHOR

       G. Wade Johnson (gwadej at cpan dot org) Paul Archer (paul at paularcher dot org)

       Houston Perl Mongers Group

       Original author: David Davis

BUGS

       Please report any bugs or feature requests to "bug-device-usb@rt.cpan.org", or through the web interface
       at <http://rt.cpan.org/NoAuth/ReportBug.html?Device::USB>.  I will be notified, and then you'll
       automatically be notified of progress on your bug as I make changes.

FOR MORE INFORMATION

       The project is hosted at Google Code <http://code.google.com/p/perl-device-usb/>.  More information on
       the project, including installation help is available on the Wiki.

LIMITATIONS

       So far, this module has only been tested on Linux. It should work on any OS that supports the libusb
       library. Several people have reported problems compiling the module on Windows. In theory, it should be
       possible to make the library work with LibUsb-Win32 <http://libusb-win32.sourceforge.net/>.  Without
       access to a Windows development system, I can't make those changes.

       The Interfaces and Endpoints are not yet proper objects. The code to extract this information is not yet
       written.

ACKNOWLEDGEMENTS

       Thanks go to various members of the Houston Perl Mongers group for input on the module. But thanks mostly
       go to Paul Archer who proposed the project and helped with the development.

       Thanks to Josep Mones Teixidor for fixing the "bInterfaceClass" bug.

       Thanks to Mike McCauley for support of "usb_get_driver_np" and "usb_detach_kernel_driver_np".

       Thanks to Vadim Mikhailov for fixing a compile problem with VC6 on Windows and then chipping in again for
       VS 2005 on Windows, and yet again to fix warnings on C99-compliant compilers.

       Thanks to John R. Hogheruis for information about modifying the Inline parameters for compiling with
       Strawberry Perl on Windows.

       Thanks to Tony Shadwick for helping me resolve a problem with bulk_read and interrupt_read.

COPYRIGHT & LICENSE

       Copyright 2006-2013 Houston Perl Mongers

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl
       itself.