ndn-embedded

Cross-compiling NDN projects for Raspberry Pi

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Note: before reading this document, you should already be familiar with the basic concepts of compiling and linking (especially the linking part). If not, you may be interested in reading this great book: [Linkers and Loaders](http://www.amazon.com/Linkers-Kaufmann-Software-Engineering-Programming/dp/1558604960/ref=sr_1_1?ie=UTF8&qid=1394130356&sr=8-1&keywords=linker+and+loader)

Basic idea

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Remember to compile a C/C++ project, we need the source code for the project, the header files for the included libraries, the binary objects of the libraries, and the compiler tools (gcc, as, ld, etc.). The combination of the last three things together is referred to as a _building environment_. Cross-compiling is no different. To cross compile a project, we first need to setup the building environment and then build the source code in that environment.

Difference between "native compiling" and "cross compiling"

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The biggest difference is that for native compiling, you build the binaries that will run on the same platform where you build them. For cross compiling, however, you build the binaries in one platform and run them on another platform. The platforms may differ in the operating systems (Windows vs. Linux) and/or the CPU architecture (x86_64 vs. arm32).

Raspberry Pi platform information

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Raspberry Pi runs on *ARMv6* CPU, which is a 32bit chip with hardware float-point support (abbreviated as *armhf*). There are many operating systems available. The one we are going to use is called *Raspbian*, which is a port of the Debian "wheezy" Linux distribution.

Creating a building environment for Raspberry Pi

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To prepare a building environment, we need to get the gcc/g++ compiler tools that will generate binaries for the armhf platform.