Add CMake example

docs/_sidebar.json

@@ -56,7 +56,8 @@
         },
         "items": [
           "maintainer/example_recipes/go",
-          "maintainer/example_recipes/rust"
+          "maintainer/example_recipes/rust",
+          "maintainer/example_recipes/cmake"
         ]
       }
     ]

docs/maintainer/example_recipes/cmake.md

@@ -0,0 +1,76 @@
+---
+title: 'CMake packages'
+---
+
+If you want to package a CMake library to conda-forge, you can use this recipe template:
+
+```yaml
+context:
+  version: "1.2.3"
+
+package:
+  name: example-package
+  version: ${{ version }}
+
+source:
+  url: https://github.com/example-package/example-package/archive/refs/tags/v${{ version }}.tar.gz
+  sha256: 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef
+
+build:
+  number: 0
+  script:
+    content:
+      - if: unix
+        then:
+          - cmake -B build -GNinja $CMAKE_ARGS .
+          - cmake --build build --parallel ${CPU_COUNT}
+        else:
+          - cmake -B build -GNinja %CMAKE_ARGS% .
+          - cmake --build build --parallel %CPU_COUNT%
+      - ctest --test-dir build --output-on-failure
+      - cmake --install build
+
+requirements:
+  build:
+    - ${{ stdlib('c') }}
+    - ${{ compiler('c') }}
+    - ${{ compiler('cxx') }} # optional
+    - cmake
+    - ninja
+  host:
+    # put any dependencies here
+  run_exports:
+    - ${{ pin_subpackage('example-package', upper_bound='x.x.x') }}
+
+tests:
+  - package_contents:
+      lib:
+        - example_package
+
+about:
+  homepage: https://github.com/example-package/example-package
+  summary: Summary of the package.
+  description: |
+    Description of the package
+  license: LGPL-3.0-or-later
+  license_file:
+    - COPYING
+  documentation: https://github.com/example-package/example-package
+  repository: https://github.com/example-package/example-package
+
+extra:
+  recipe-maintainers:
+    - LandoCalrissian
+```
+
+This recipe template supports different features:
+
+- `$CMAKE_ARGS` (or `%CMAKE_ARGS%` on Windows) is set by conda-forge and contains flags needed for cross-compilation, installation prefix, and other platform-specific settings. Always pass it to the `cmake` configure step.
+- `-GNinja` selects the Ninja build system generator, which is faster than the default Make generator.
+- `--parallel ${CPU_COUNT}` passes the number of available CPUs to the build step to enable parallel compilation.
+- `ctest --test-dir build --output-on-failure` runs the project's test suite during the build phase (while the build directory is still available) and prints output from any failing tests.
+- `run_exports` with `pin_subpackage` ensures that downstream packages that depend on this library automatically get a compatible version pinned at build time.
+
+If your project is a standalone executable rather than a library, you can remove the `run_exports` section and adjust the `package_contents` test to check `bin` instead of `lib`.
+
+If your project does not use C++, you can remove the `${{ compiler('cxx') }}` line from the build requirements.