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.\"
.IX Title "Device::USB::Bus 3pm"
.TH Device::USB::Bus 3pm 2024-03-07 "perl v5.38.2" "User Contributed Perl Documentation"
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.SH NAME
Device::USB::Bus \- Use libusb to access USB devices.
.SH VERSION
.IX Header "VERSION"
Version 0.38
.SH SYNOPSIS
.IX Header "SYNOPSIS"
This class encapsulates the USB bus structure and provides methods for
retrieving data from it. This class is not meant to be used alone, it is
part of the Device::USB package.
.PP
Device:USB:LibUSB provides a Perl wrapper around the libusb library. This
supports Perl code controlling and accessing USB devices.
.PP
.Vb 1
\&    use Device::USB;
\&
\&    my $usb = Device::USB\->new();
\&
\&    foreach my $bus ($usb\->list_busses())
\&    {
\&        print $bus\->dirname(), ":\en";
\&        foreach my $dev ($bus\->devices())
\&        {
\&            print "\et", $dev\->filename(), "\en";
\&        }
\&    }
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
This module provides a Perl interface to the bus structures returned by the
libusb library. This library supports a read-only interface to the data libusb
returns about a USB bus.
.SH FUNCTIONS
.IX Header "FUNCTIONS"
.IP dirname 4
.IX Item "dirname"
Return the directory name associated with this bus.
.IP location 4
.IX Item "location"
Return the location value associated with this bus.
.IP devices 4
.IX Item "devices"
In array context, it returns a list of Device::USB::Device objects
representing all of the devices on this bus. In scalar context, it returns a
reference to that array.
.IP find_device_if 4
.IX Item "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.
.RS 4
.IP pred 4
.IX Item "pred"
the predicate used to select a device
.RE
.RS 4
.Sp
returns a device reference or undef if none was found.
.RE
.IP "list_devices_if This method provides a 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." 4
.IX Item "list_devices_if This method provides a 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."
.RS 4
.PD 0
.IP pred 4
.IX Item "pred"
.PD
coderef to test devices.
.RE
.RS 4
.Sp
For example,
.Sp
.Vb 3
\&    my @devices = $bus\->list_devices_if(
\&        sub { Device::USB::CLASS_HUB == $_\->bDeviceClass() }
\&    );
.Ve
.Sp
Returns all USB hubs found on this bus. The device to test is available to
the coderef in the \f(CW$_\fR variable for simplicity.
.RE
.SH DIAGNOSTICS
.IX Header "DIAGNOSTICS"
This is an explanation of the diagnostic and error messages this module
can generate.
.SH DEPENDENCIES
.IX Header "DEPENDENCIES"
This module depends on the Carp and Device::USB, as well as
the strict and warnings pragmas. Obviously, libusb must be available since
that is the entire reason for the module's existence.
.SH AUTHOR
.IX Header "AUTHOR"
G. Wade Johnson (gwadej at cpan dot org)
Paul Archer (paul at paularcher dot org)
.PP
Houston Perl Mongers Group
.SH BUGS
.IX Header "BUGS"
Please report any bugs or feature requests to
\&\f(CW\*(C`bug\-device\-usb@rt.cpan.org\*(C'\fR, 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.
.SH ACKNOWLEDGEMENTS
.IX Header "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.
.PP
Thanks also go to Josep Monés Teixidor, Mike McCauley, and Tony Awtrey for
spotting, reporting, and (sometimes) fixing bugs.
.SH "COPYRIGHT & LICENSE"
.IX Header "COPYRIGHT & LICENSE"
Copyright 2006\-2013 Houston Perl Mongers
.PP
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.