C and C++

This guide provides tips and hints for building C and C++ projects.

Overview

GNU C and C++ compilers are pre-installed in the Semaphore environment. You can switch the active compiler using sem-version on Linux machines.

How to compile C

The Ubuntu Linux machines ship with the GNU C compiler.

Editor

1. Open the pipeline

2. Select one of the Linux Ubuntu machines

3. Use the following commands in the job

   checkout
   gcc --version
   gcc hello.c -o hello
   ./hello

   

4. Press Run the workflow

YAML

1. Open the pipeline file
2. Select one of the Linux Ubuntu agents
3. Add a job to compile the source code with gcc
4. Save and push the pipeline file to the repository

version: v1.0
name: Initial Pipeline
agent:
  machine:
    type: e1-standard-2
    os_image: ubuntu2004
blocks:
  - name: Compile
    dependencies: []
    task:
      jobs:
        - name: gcc
          commands:
            - checkout
            - gcc --version
            - gcc hello.c -o hello
            - ./hello

See artifacts to learn how to save and persist the built binary.

How to change gcc version

Use sem-version to switch between gcc compiler versions on Linux. Changing gcc compilers on macOS is not supported.

# use gcc 10.5
sem-version c 10
$ gcc --version
gcc (Ubuntu 10.5.0-1ubuntu1~20.04) 10.5.0

# use gcc 9.4
sem-version c 9
$ gcc --version
gcc (Ubuntu 9.4.0-1ubuntu1~20.04.2) 9.4.0

Using Docker containers

The sem-version tool does not work on Docker containers. If the compiler you need is not shipped in the Semaphore Linux or macOS image, you must build a Docker image and run jobs using Docker environments.

Semaphore does not provide pre-built C and C++ Docker images. Find Dockerfiles to build your custom images in the semaphoreci/docker-images repository.

How to compile C++

The Ubuntu Linux machines ship with the GNU C++ compiler.

Editor

1. Open the pipeline

2. Select one of the Linux Ubuntu machines

3. Use the following commands in the job

   checkout
   g++ --version
   g++ hello.cc -o hello
   ./hello

   

4. Press Run the workflow

YAML

1. Open the pipeline file
2. Select one of the Linux Ubuntu agents
3. Add a job to compile the source code with gcc
4. Save and push the pipeline file to the repository

version: v1.0
name: Initial Pipeline
agent:
  machine:
    type: e1-standard-2
    os_image: ubuntu2004
blocks:
  - name: Compile
    dependencies: []
    task:
      jobs:
        - name: g++
          commands:
            - checkout
            - g++ --version
            - g++ hello.cc -o hello
            - ./hello

See artifacts to learn how to save and persist the built binary.

How to change the g++ version

Use sem-version to switch between g++ compiler versions on Linux. Changing gcc compilers on macOS is not supported..

# use gcc 10.5
sem-version cpp 10
$ g++ --version
g++ (Ubuntu 10.5.0-1ubuntu1~20.04) 10.5.0

# use gcc 9.4
sem-version cpp 9
$ g++ --version
g++ (Ubuntu 9.4.0-1ubuntu1~20.04.2) 9.4.0