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= Toolchains installation =

A cross toolchain is needed to compile on your computer a program for a target (different achitecture). A toolchain is needed to compile on your computer programs for your computer.

All toolchains/cross toolchains only supports x86_64 hosts (32 bits hosts are not supported).

Toolchains have been built with [https://github.com/2rm-robotics/robomap3-rt robomap3] project, based on poky. They package everything you need for flair.

__NOTE__: for sake of simplicity, the word compilation can be used in this documentation for both cross compilation and compilation

== Toolchain for x86_64 (mandatory) ==

You need at least this one, as it used for compiling FlairGCS and other tools.

{{{
$ cd ~
$ wget https://uav.hds.utc.fr/src/toolchain/x86_64-meta-toolchain-flair-x86_64.sh
$ chmod +x x86_64-meta-toolchain-flair-x86_64.sh
$ sudo ./x86_64-meta-toolchain-flair-x86_64.sh
$ rm x86_64-meta-toolchain-flair-x86_64.sh
}}}

== Cross toolchain for armv7a-neon (ardrone2, bebop, hds x8)  ==

{{{
$ cd ~
$ wget https://uav.hds.utc.fr/src/toolchain/x86_64-meta-toolchain-flair-armv7a-neon.sh
$ chmod +x x86_64-meta-toolchain-flair-armv7a-neon.sh
$ sudo ./x86_64-meta-toolchain-flair-armv7a-neon.sh
$ rm x86_64-meta-toolchain-flair-armv7a-neon.sh
}}}

== Cross toolchain for armv5e (mambo)  ==

{{{
$ cd ~
$ wget https://uav.hds.utc.fr/src/toolchain/x86_64-meta-toolchain-flair-armv5e.sh
$ chmod +x x86_64-meta-toolchain-flair-armv5e.sh
$ sudo ./x86_64-meta-toolchain-flair-armv5e.sh
$ rm x86_64-meta-toolchain-flair-armv5e.sh
}}}


== Setup files ==

Each toolchain install 2 important files needed for compilation:
* ''environment-setup-arch-poky-linux-gnueabi'': a script to source if you need to compile something manually, without CMake. For example ''/opt/robomap3/2.1.3/armv5te/environment-setup-armv5e-poky-linux-gnueabi''
* ''toolchain.cmake'': a file used by CMake to get all information needed to compile with this toolchain. For example ''/opt/robomap3/2.1.3/armv5te/toolchain.cmake''

The first one can be used to compile a kernel for example. The second one is needed for each CMake project, but is automatically used by the [wiki:compile_all#Helperscripts helper scripts], so you should not have to bother with it, unless you want to build a CMake project not in the flair build system.

== Environment variable == 

Toolchain installation scripts add variables in ''.bashrc''. If you need to use it directly in the same terminal or an already opened one, reload your ''.bashrc''
{{{
$ source ~/.bashrc
}}}

These variables are:
* ''OECORE_CMAKE_TOOLCHAINS'': a list of installed toolchains (for example ''core2_64 armv7a_neon armv5te'')
* ''OECORE_CMAKE_arch_TOOLCHAIN'': where ''arch'' is from the previous list (for example ''OECORE_CMAKE_CORE2_64_TOOLCHAIN''). Location of the ''toolchain.cmake'' file for a specific architecture
* ''OECORE_HOST_SYSROOT'': used by ground control station to retrieve maps provider plugins (for gps)
* ''OECORE_HOST_NATIVE_SYSROOT'': used to retrieve host's cmake and doxygen tools.