11.2. C++

C++ has no language-level package manager, so a C++ pool’s dependencies are external system libraries: the environment provisions the library (its headers and shared objects) and the pool links against it.

11.2.1. Library dependencies (cpp-deps)

Declare the libraries a module needs in its package.yaml under cpp-deps, using package: version-constraint:

cpp-deps:
  boost: ">=1.80"

cpp-deps are provisioned from the conda-forge package database — installing the library’s headers and shared objects into the environment. conda is the default (and only) source, so the bare form above is equivalent to boost: {version: ">=1.80", source: conda}. The compiler takes the union across every imported module and the solver intersects conflicting constraints.

A cpp-deps entry may also name a conda channel other than conda-forge (see the Python chapter for the full rules), for a library that lives on a subordinate channel.

11.2.2. Link flags (dependencies)

Provisioning a library makes its headers available, but linking against a compiled component also needs a linker flag. List the link names under dependencies (a bare list); each entry foo becomes -lfoo on the pool’s compile line:

cpp-deps:
  boost: ">=1.80"
dependencies:
  - boost_filesystem
  - boost_system

A header-only library (or a header-only part of a larger one) needs only cpp-deps and no -l flag. For any other compiler flags — extra include paths, -DFOO, -O3, -march=native — use cxx-flags, a bare list appended verbatim to the compile line. All three fields propagate transitively through a module’s dependencies.

The local-deps section that Python and Rust use for in-project packages (Local packages (local-deps)) is not available for C++, which has no package manager to track such an install; a library you build yourself is linked through dependencies and cxx-flags like any other.