Conan - C/C++ Package Manager

Conan is a package manager for C and C++. It helps developers manage dependencies, build configurations, and package binaries in a reproducible way. Since C++ has no single standardized build or package system (unlike Java with Maven or Rust with Cargo), Conan fills that gap. Works across operating systems, compilers (GCC, Clang, MSVC), and build systems (CMake, Meson, Autotools, etc.).

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2. Core Concepts

• Packages & Recipes

  • A Conan package = a binary or source distribution of a C/C++ library.
  • Defined by a conanfile.py or conanfile.txt (recipe).

• Conan Center

  • The central repository hosting popular C++ packages.

• Profiles

  • Define build settings (compiler, version, build type, architecture).
  • Example: default profile for dev, release profile for production.

• Settings & Options

  • Settings: compiler, OS, architecture.
  • Options: package-specific toggles (e.g., enable/disable SSL support).

• Remotes

  • Repositories (ConanCenter, Artifactory, custom remotes).

• Lockfiles

  • Ensure reproducible dependency resolution.

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3. Important Sections / Files

• conanfile.txt (simpler, dependency list)

  [requires]
  fmt/9.1.0
  spdlog/1.11.0
  
  [generators]
  cmake

• conanfile.py (full recipe)

  from conan import ConanFile
  
  class HelloConan(ConanFile):
      name = "hello"
      version = "0.1"
      settings = "os", "compiler", "build_type", "arch"
      requires = "fmt/9.1.0"
      generators = "CMakeDeps"

• conan.lock

  • Lockfile for reproducibility (pinned versions + options).

• Profiles (~/.conan2/profiles/)

  • Example:

    [settings]
    os=Linux
    compiler=gcc
    compiler.version=11
    build_type=Release
    arch=x86_64

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4. Modern Way of Working with Conan (v2)

• Use Conan 2.x (released 2023) — major redesign for clarity and consistency.
• Use CMakeDeps + CMakeToolchain generators instead of legacy ones.
• Prefer lockfiles for reproducible builds.
• Use profiles to separate build configs (debug/release, cross-compilation).
• Integrate Conan with CI/CD (GitHub Actions, GitLab CI, Jenkins).
• Upload custom packages to Artifactory or private remotes.

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5. Build Systems Conan Integrates With

Conan is not itself a build system (like Cargo) but integrates tightly with many:

• CMake → Primary build system integration (CMakeDeps, CMakeToolchain).
• Meson → Supported via generators.
• Autotools / Makefiles → Supported.
• Bazel → Third-party integrations.
• Visual Studio / Xcode → Integration via toolchains.

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6. Creating Optimized Builds with Conan

• Dependency Management

  • Use version ranges (fmt/[>=9.0 <10.0]) for flexibility.
  • Use lockfiles for reproducibility.
  • Vendor private packages into your own Artifactory.

• Profiles & Multi-Config

  • Define profiles for Debug/Release/Cross-compilation.
  • Example: cross-compiling to ARM with a separate profile.

• Performance

  • Use prebuilt binaries (Conan caches them).
  • Build once, deploy everywhere (avoids per-developer builds).

• Reproducibility

  • Always commit lockfiles for applications.
  • Use conan create + conan upload for distributing consistent binaries.

• CI/CD Optimization

  • Cache ~/.conan2 in pipelines.
  • Use profiles per environment (Linux, Windows, macOS).
  • Automate package uploads after successful builds.