cross compiling - What's the difference between --host and --target in gcc?

Question

There are three system names that the build knows about: the machine you are building on (build), the machine that you are building for (host), and the machine that GCC will produce code for (target). When you configure GCC, you specify these with ‘--build=’, ‘--host=’, and ‘--target=’.

Aren't the machine that you are building for and the machine that GCC will produce code for the same thing? What's the difference?

Answer 1

It's possible to build gcc as a cross compiler. That is, you can build a gcc that runs on one architecture (the host) but generates code for a different architecture (the target).

The common place you'll come across this is when building code for embedded platforms. If you're writing code for the processor in your fridge, you'd kind of like to build it on your desktop, not in the fridge!

Some folks use cross compilers to build code for a different OS on the same architecture. For example, it's possible to target Windows from a Linux host with the MinGW toolchain.