Build

Building the Library

Prerequisites

Table 1: Prerequisites for building the library.
Software Minimal Version Comment
Linux 2.6.32  
gcc (clang) 4.7 (3.3) both gcc and clang are supported
libcurl 7.26.0 older versions might work, but not tested
Lua 5.0 optional, for Lua plugin support only

Compiling the Library

First, download a copy of the library from the git repository and change to the directory.

$ git clone git@bitbucket.org:m2m/cumulocity-sdk-c.git
$ cd cumulocity-sdk-c

Second, initialize and update your submodule dependencies, since the library depends on the paho.mqtt.embedded-c library for MQTT support.

$ git submodule init
$ git submodule update

Then, create a init.mk file, and define specific macros CPPFLAGS, CXXFLAGS and LDFLAGS, LDLIBS and CXX if cross-compiling.

CXX:=/usr/bin/g++
CPPFLAGS:=-I/usr/include
CXXFLAGS:=-Wall -pedantic -Wextra
LDFLAGS:=-L/usr/lib
LDLIBS:=-lcurl

Listing 3 shows a typical init.mk file example. In essence, init.mk defines search path for required c++ header files, preferred warning levels, search path for required c++ library files, and necessary linking flags.

When you do host compiling, many of these settings can obviously be omitted, these are more relevant for cross-compiling, which shall be the prevalent use case for the library. Later we will explain the init.mk file is also very important for another purpse, i.e., build customization to tailor the library to your needs.

With the init.mk being defined, it's time to define your makefile.

$ cp Makefile.template Makefile

The default Makefile.template can be used unchanged in most cases. In case some settings are not suitable for your use case, e.g., you may want -Os optimization level instead of the default -O2, simply edit the copied Makefile.

Now we have done all preparation work, it's time to build the library for your target device.

$ make

If everything is configured correctly, this should compile the library and output the final binary into the lib/ directory, and a watchdog daemon srwatchdogd into the bin/ directory in the root directory.

The build system supports both debug and release modes. The above command calling make without any target defaults to debug build. debug build produces much larger binary, more verbose output, etc, which is suitable for development phase. When releasing your software, you will likely want a release build, you can clear all intermediate build files and re-build the library in release mode when you want to release your software.

$ make clean
$ make release

Footnotes:

1 You can also access the library repository at https://bitbucket.org/m2m/cumulocity-sdk-c.