liblo

liblo is a lightweight library that provides an easy to use implementation of the OSC protocol. For more information about the OSC protocol, please see:

• OSC at CNMAT
• https://opensoundcontrol.stanford.edu/
• https://en.wikipedia.org/wiki/Open_Sound_Control

The official liblo homepage is here:

• liblo homepage

liblo is portable to most UNIX systems (including OS X) and Windows. It is released under the GNU Lesser General Public Licence (LGPL) v2.1 or later. See COPYING for details.

Building

To build and install liblo, read INSTALL in the main liblo directory. liblo is configured as a dynamically-linked library. To use liblo in a new application, after

configure

you should install liblo with

make install

so that the liblo library can be located by your application.

To build with MS Visual Studio on Windows, please use CMake as described next. See build/README.md for more details.

Building with CMake

If you prefer the CMake build system, support has been added. Instead of the configure step listed in the previous section, create a build directory and initialize CMake:

mkdir ~/build/liblo
cmake ~/source/liblo/cmake <more options..>
make

Examples

See examples for example source code for a simple client and two servers:

• example_server.c uses lo_server_thread_start() to create a liblo server in an separate thread.

• nonblocking_server_example.c uses select() to wait for either console input or OSC messages, all in a single thread.

• example_client.c uses liblo to send OSC messages to a server.

These examples will work without installing liblo. This is accomplished by a shell script. For example, examples/client_example is a shell script that runs the “real” program examples/.libs/example_client. Because of this indirection, you cannot run example_client with a debugger.

Debugging

To debug applications using liblo, one option is to include all the liblo source code in the application rather than linking with the liblo library. For more information about this, please see the (libtool manual)1

To compile liblo with debugging flags, use,

./configure --enable-debug

IPv6 NOTICE

liblo was written to support both IPv4 and IPv6, however it has caused various problems along the way because most of the currently available OSC applications like Pd and SuperCollider don’t listen on IPv6 sockets. IPv6 is currently disabled by default, but you can enable it using

./configure --enable-ipv6

Poll() vs Select()

Some platforms may have both poll() and select() available for listening efficiently on multiple servers/sockets. In this case, liblo will default to using poll since it is considered to be more scalable. However, on some platforms (e.g. MacOS) the liblo code path using select() is considerably faster. You may wish to explictly disable support for poll if your applications do not require extreme scalability and are sensitive to small differences in efficiency. This can be done when compiling the library from source, either using configure:

./configure --disable-poll

or if using cmake:

cmake -DWITH_POLL=OFF <path>