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# Building C++ Client

## Compile and Test:

### Compile

#### Unix
To compile the cpp client, use the following command:
`mvn clean package -P with-cpp -pl iotdb-client/client-cpp -am -DskipTests`

#### Windows
To compile on Windows, please install Boost first and add following Maven
settings:
```
-Dboost.include.dir=${your boost header folder} -Dboost.library.dir=${your boost lib (stage) folder}` 
```

The thrift dependency that the cpp client uses is incompatible with MinGW, please use Visual 
Studio. It is highly recommended to use Visual Studio 2022 or later.

##### Visual Studio 2022
If you are using Visual Studio 2022, you can compile the cpp client with the following command:

```
mvn clean package -P with-cpp -pl iotdb-client/client-cpp -am -DskipTests
-D"boost.include.dir"="D:\boost_1_75_0" -D"boost.library.dir"="D:\boost_1_75_0\stage\lib"
```

##### Visual Studio 2019
If you are using Visual Studio 2019, you can compile the cpp client with the following command:

```
mvn clean package -P with-cpp -pl iotdb-client/client-cpp -am -DskipTests
-D"boost.include.dir"="D:\boost_1_75_0" -D"boost.library.dir"="D:\boost_1_75_0\stage\lib"
-Diotdb-tools-thrift.version=0.14.1.1-msvc142-SNAPSHOT -Dcmake.generator="Visual Studio 16 2019"
```

#### Visual Studio 2017 or older
If you are using Visual Studio 2017 or older, the pre-built Thrift library is incompatible. You 
will have to compile the thrift library manually:

1. Install the dependencies of Thrift:
* flex http://gnuwin32.sourceforge.net/packages/flex.htm
* bison http://gnuwin32.sourceforge.net/packages/bison.htm
* openssl https://slproweb.com/products/Win32OpenSSL.html

2. Clone the repository: https://github.com/apache/iotdb-bin-resources.

3. Enter the "iotdb-tools-thrift" folder in the cloned repository; use the following command to 
   compile the thrift library:

`mvn install`

4. If you encounter a problem like "cannot find 'unistd.h'", please open the file
"iotdb-bin-resources\iotdb-tools-thrift\target\build\compiler\cpp\thrift\thriftl.cc" and replace
"#include <unistd.h>" with "#include <io.h>" and "#include <process.h>"; then, rerun the command 
   in the third step;

5. Return to the cpp client repository and compile it with:

```
mvn clean package -P with-cpp -pl iotdb-client/client-cpp -am -DskipTests
-D"boost.include.dir"="D:\boost_1_75_0" -D"boost.library.dir"="D:\boost_1_75_0\stage\lib"
```


### Test
First build IoTDB server together with the cpp client.

Explicitly using "install" instead of package in order to be sure we're using libs built on this 
machine.

`mvn clean install -P with-cpp -pl distribution,iotdb-client/client-cpp -am -DskipTests`

After run verify

`mvn clean verify -P with-cpp -pl iotdb-client/client-cpp -am`

## Code Formatting

We use `clang-format` as the only formatter for C++ code and trigger it through Maven Spotless.

### Required version

The version is pinned in the root `pom.xml` as property `clang.format.version` (same approach as Apache TsFile). Use **clang-format 17.0.6** locally so Spotless agrees with CI.

**JDK for Maven:** the C++ `clangFormat` step is registered only when running Maven on **JDK 11 or newer** (see the `spotless-cpp` profile in this module and in `client-cpp-example`). The repository root still supports JDK 8 for Java builds, but `spotless:check` / `spotless:apply` for C++ will not apply the clang-format rules if you use JDK 8.

### Install clang-format 17.0.6

- Linux (Ubuntu): On **24.04+**, `sudo apt-get install -y clang-format-17`. On **22.04**, that package is not in the default archive; add the LLVM 17 repo with [apt.llvm.org](https://apt.llvm.org/) (e.g. `sudo ./llvm.sh 17`, as CI does). The script installs `clang-17` and related tools but **not** the `clang-format-17` package, so also run `sudo apt-get install -y clang-format-17`. Then point the default `clang-format` at 17.x (Spotless invokes `clang-format` on `PATH`; some releases default to another major version):

  `sudo update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-17 100`

  `sudo update-alternatives --set clang-format /usr/bin/clang-format-17`

- macOS: `brew install llvm@17`, then e.g. `ln -sf "$(brew --prefix llvm@17)/bin/clang-format" "$(brew --prefix)/bin/clang-format"` and/or put `$(brew --prefix llvm@17)/bin` on your `PATH`.

- Windows: `choco install llvm --version=17.0.6 --force -y` (CI uses `--force` like TsFile so the expected LLVM is selected).

### Validate only (no changes)

`./mvnw -P with-cpp -pl iotdb-client/client-cpp spotless:check`

`./mvnw -P with-cpp -pl example/client-cpp-example spotless:check`

### Auto-fix formatting

`./mvnw -P with-cpp -pl iotdb-client/client-cpp spotless:apply`

`./mvnw -P with-cpp -pl example/client-cpp-example spotless:apply`

### Windows (PowerShell)

PowerShell may treat a comma in `-pl` as an argument separator. Prefer the two commands above. If you need a single invocation, quote the whole `-pl` value, for example:

`./mvnw -P with-cpp "-pl=iotdb-client/client-cpp,example/client-cpp-example" spotless:check`

## Package Hierarchy

If the compilation finishes successfully, the packaged zip file will be placed under
"client-cpp/target/client-cpp-${project.version}-cpp-${os}.zip". 

On macOS, the hierarchy of the package should look like this:
```
.
+-- client
|   +-- include
|       +-- Session.h
|       +-- IClientRPCService.h
|       +-- client_types.h
|       +-- common_types.h
|       +-- thrift
|           +-- thrift_headers...
|   +-- lib
|       +-- Release
|          +-- libiotdb_session.dylib
|          +-- parser.dylib
|          +-- thriftmd.dylib
|          +-- tutorialgencpp.dylib
```

## Using C++ Client:
```
1. Put the zip file "client-cpp-${project.version}-cpp-${os}.zip" wherever you want;

2. Unzip the archive using the following command, and then you can get the two directories 
mentioned above, the header file and the dynamic library:
    unzip client-cpp-${project.version}-cpp-${os}.zip

3. Write C++ code to call the operation interface of the cpp client to operate IoTDB,
    for detail interface information, please refer to the link: https://iotdb.apache.org/UserGuide/latest/API/Programming-Cpp-Native-API.html

   E.g:
    #include "include/Session.h"
    #include <memory>
    #include <iostream>

    int main() {
        std::cout << "open session" << std::endl;
        std::shared_ptr<Session> session(new Session("127.0.0.1", 6667, "root", "root"));
        session->open(false);

        std::cout << "setStorageGroup: root.test01" << std::endl;
        session->setStorageGroup("root.test01");

        if (!session->checkTimeseriesExists("root.test01.d0.s0")) {
            session->createTimeseries("root.test01.d0.s0", TSDataType::INT64, TSEncoding::RLE, CompressionType::SNAPPY);
            std::cout << "create Timeseries: root.test01.d0.s0" << std::endl;
        }

        std::cout << "session close" << std::endl;
        session->close();
    }

4. Compile and execute
    clang++ -O2 user-cpp-code.cpp -liotdb_session -L/user-unzip-absolute-path/lib -Wl,-rpath /user-unzip-absolute-path/lib -std=c++11
    ./a.out
```