Add initial CMake build support.

[drewnoakes]

This CMakeLists.txtprovides targets forunittests,perftests` and all example programs.

Note that this file does not copy the bin folder contents to the target directory, which only applies if you do out-of-source builds. In which case you may copy the folder manually, or ideally update CMakeLists.txt to perform this. I didn't manage to get this to work.

It's possible the minimum CMake version required is actually lower than that published, but I cannot test. Users of this file on earlier versions should modify this if earlier versions do in fact work.

To use:

rapidjson$ mkdir out
rapidjson$ cd out
rapidjson/out$ cmake ..
rapidjson/out$ make unittests

This CMake file has also been tested with beta builds of the new CLion IDE and works well.

You may also configure the build using a tool such as ccmake.

rapidjson/out$ ccmake .

[miloyip]

Thank you for this. We would like to have CMAKE build.

I am not familiar with CMAKE. Is it possible to do some wildcards of files instead of explicitly listing them? Otherwise it may be easily broken if a file is added or removed, isn't it?

[drewnoakes]

That does seem attractive, but it doesn't seem to be a common practice. I think this explains why:

It is tempting to use this command to avoid writing the list of source files for a library or executable target. While this seems to work, there is no way for CMake to generate a build system that knows when a new source file has been added. Normally the generated build system knows when it needs to rerun CMake because the CMakeLists.txt file is modified to add a new source. When the source is just added to the directory without modifying this file, one would have to manually rerun CMake to generate a build system incorporating the new file.

This is pretty minimal as far as CMake configurations go, in my experience.

What other compile flags would you like? For example I expect we should add -Wall and maybe -Wextra and -Werror.

[miloyip]

Currently gmake version has -march=native -Wall -Wextra -Werror -Weffc++ -Wswitch-default for unit test.

[drewnoakes]

Some improvements, rebased on top of master.

• Using the same compiler flags as those @miloyip quoted from gmake
• Google test now built as a lib using its own CMake file
• Removal of all header files -- CMake can deduce these dependencies itself

The file is much simpler now, fitting on one screen.

Otherwise it may be easily broken if a file is added or removed, isn't it?

In practice this isn't an issue, so long as someone is using the CMake file. It might be a good idea to have the CI server run an additional build using CMake, just to ensure everything is alright with its configuration.

[miloyip]

Can you also help adding instructions in readme?