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# Minimal C++ build example

This directory showcases a minimal build of Arrow C++ (in `build_arrow.sh`).
This minimal build is then used by an example third-party C++ project
using CMake logic to compile and link against the Arrow C++ library
(in `build_example.sh` and `CMakeLists.txt`).

When run, the example executable reads a file named `test.csv`,
displays its parsed contents, and then saves them in Arrow IPC format in
a file named `test.arrow`.

## Running the example

You can run this simple example using [Docker Compose][docker-compose]
and the given `docker-compose.yml` and dockerfiles, which installs a
minimal Ubuntu image with a basic C++ toolchain.

Just open a terminal in this directory and run the following commands:

```bash
docker-compose run --rm minimal
```

Note that this example mounts two volumes inside the Docker image:
* `/arrow` points to the Arrow source tree
* `/io` points to this example directory

## Statically-linked builds

We've provided an example build configuration here with CMake to show how to
create a statically-linked executable with bundled dependencies.

To run it on Linux, you can use the above Docker image:

```bash
docker-compose run --rm static
```

On macOS, you can use the `run_static.sh` but you must set some environment
variables to point the script to your Arrow checkout, for example:

```bash
export ARROW_DIR=path/to/arrow-clone
export EXAMPLE_DIR=$ARROW_DIR/cpp/examples/minimal_build
export ARROW_BUILD_DIR=$(pwd)/arrow-build
export EXAMPLE_BUILD_DIR=$(pwd)/example

./run_static.sh
```

On Windows, you can run `run_static.bat` from the command prompt with Visual
Studio's command line tools enabled and CMake and ninja build in the path:

```
call run_static.bat
```

### Static linking against system libraries

You can also use static libraries of Arrow's dependencies from the
system. To run this configuration, set
`ARROW_DEPENDENCY_SOURCE=SYSTEM` for `run_static.sh`. You can use
`docker-compose` for this too:

```bash
docker-compose run --rm static-system-dependency
```

[docker-compose]: https://docs.docker.com/compose/
