upm/docs/building.md

Building UPM {#building}

UPM uses cmake in order to make compilation relatively painless. Cmake runs build out of tree so the recommended way is to clone from git and make a build/ directory. Failure to do an out-of-source build may cause issues when rebuilding later on.

This project depends on libmraa, so that needs to be installed first. Use the following environment variables to configure the paths:

PKG_CONFIG_PATH=$PKG_CONFIG_PATH:.../mraa/build/lib/pkgconfig
CPLUS_INCLUDE_PATH=$CPLUS_INCLUDE_PATH:.../mraa/build/include
LIBRARY_PATH=$LIBRARY_PATH:.../mraa/build/lib

UPM will attempt to build all directories inside src/ and they must contain individual CMakeLists.txt files.

mkdir build
cd build
cmake ..
make

Our cmake configure has a number of options, cmake-gui or ccmake can show you all the options. The interesting ones are detailed below:

Changing install path from /usr/local to /usr

-DCMAKE_INSTALL_PREFIX:PATH=/usr

Building debug build:

-DCMAKE_BUILD_TYPE=DEBUG

Using clang instead of gcc:

-DCMAKE_C_COMPILER=/usr/bin/clang -DCMAKE_CXX_COMPILER=/usr/bin/clang++

Cross-compiling on a different system:

-DCMAKE_CXX_FLAGS:STRING=-m32 -march=i586
-DCMAKE_C_FLAGS:STRING=-m32 -march=i586

Building with an older version of swig (swig 2.0+) requires the disabling of javascript:

-DBUILDSWIGNODE=OFF

Disabling python module building

-DBUILDSWIGPYTHON=OFF

Setting the python library to use:

-DPYTHON_LIBRARY:FILEPATH=/usr/lib/libpython2.7.so.1.0

Building doxygen doc

-BUILDDOC=ON

If you intend to turn on all the options and build everything at once (C++, Node, Python and Documentation) you will have to edit the src/doxy2swig.py file and change the line endings from Windows style to Linux format. This has to be repeated every time to sync with the master branch since our Github repository stores files using CR LF line breaks.

You can also generate the include and lib directories containing all the sensor headers and library files respectively with make install. Further, you may choose to generate these only for a specific sensor you modified, and this can be achieved by building from the individual makefile of the sensor. Assuming you’re in the build directory, to make the lcd module you would:

cd src/lcd
make install

Often developers are only interested in building one module or even just the python/node module to do some quick testing using scripting. In order to do this you need to use the target name for the python or node module you want to rebuild. For example the lcd module target name is i2clcd. Therefore the python module target name will be prefixed by pyupm. Just do the following to build only that module. Modules not using the UPM cmake macros may have different naming.

make _pyupm_i2clcd

Sometimes you want to build a small C++ example against an installed library. This is fairly easy if installed system-wide. Just link against the correct library (in this case libupm-tm1637) and then add /usr/include/upm to the loader path:

g++ test.cxx -lupm_tm1637 -I/usr/include/upm

You can also use pkg-config to return the information to you, which is considered the correct way if including UPM in a build system like cmake or autotools on linux.

pkg-config --cflags --libs upm-tm1637