features无法添加cxxflags、defines，导致eigen编译无法使用-DEIGEN_USE_BLAS宏 #180

Activity

1. Sunrisepeak commented on Jun 28, 2026

   

   Sunrisepeak

   on Jun 28, 2026

   Member

   More actions

   header only 库比较简单编写, 只要指定 include 目录就可以了。
   你可以给 mcpp-index 添加 eigen的支持 compat.eigen.lua

   具体可以参考, 指定头文件目录即可

   • https://github.com/mcpplibs/mcpp-index/blob/main/pkgs/c/compat.imgui.lua

   

   详细PR参考

   • feat: CN 资源镜像 (mcpp-res) + GLOBAL/CN url 表 mcpplibs/mcpp-index#41
2. tz12323 commented on Jun 28, 2026

   

   tz12323

   on Jun 28, 2026

   Last edited by tz12323

   Author

   More actions

   已完成对Eigen+blas的支持，详见个人仓库https://github.com/tz12323/eigen.git。暂时不确定是否链接上了Eigen自带的blas，单Eigen调用成功。lapack暂时没有写对应的mcpp.toml

   [workspace]
   members = ["blas"]
   [package]
   name = "eigen"
   version = "5.0.0"
   
   [targets.eigen]
   kind = "lib"
   
   [targets.eigen_blas]
   kind = "lib"
   required_features = ["blas"]
   cxxflags = ["-DEIGEN_USE_BLAS"]
   
   [build]
   opt = 3
   include_dirs = ["."]
   
   [dependencies.eigen_blas]
   blas = { path = "./blas" }
   

   在我自己调用这个包时，发现指定了features为blas后并没有在compile_command.json中找到EIGEN_USE_BLAS这个定义
3. Sunrisepeak commented on Jun 28, 2026

   

   Sunrisepeak

   on Jun 28, 2026

   Last edited by Sunrisepeak

   Member

   More actions

   @tz12323 eigen的库支持已经添加到了mcpp-index索引中

   如果是自己定制的库, 可以像上面自己定义mcpp.toml实现, 默认官方的目前可以直接通过包名使用

   • https://mcpplibs.github.io/mcpp-index/packages/compat.eigen.html
   • https://github.com/mcpplibs/mcpp-index/tree/main/tests/examples/eigen

   默认使用

   [dependencies]
   compat.eigen = "5.0.1"
   

   开启blas支持

   [dependencies]
   compat.eigen = { version = "5.0.1", features = ["blas"] }
   
4. Sunrisepeak

   changed the title [-]对head-only库的支持[/-] [+]对head-only库的支持 - 例如Eigen[/+] on Jun 28, 2026
5. tz12323 commented on Jun 28, 2026

   

   tz12323

   on Jun 28, 2026

   Author

   More actions

   @Sunrisepeak 在调用安装compat.eigen并且启用blas这个features后,只在compile_command.json中找到了-DMCPP_FEATURE_BLAS这个宏定义,并没有找到-DEIGEN_USE_BLAS这个宏定义.说明了blas特性并没有被启用.
6. tz12323

   changed the title [-]对head-only库的支持 - 例如Eigen[/-] [+]features无法添加cxxflags、defines，导致eigen编译无法使用-DEIGEN_USE_BLAS宏[/+] on Jun 28, 2026
7. Sunrisepeak commented on Jun 29, 2026

   

   Sunrisepeak

   on Jun 29, 2026

   Member

   More actions

   @Sunrisepeak 在调用安装compat.eigen并且启用blas这个features后,只在compile_command.json中找到了-DMCPP_FEATURE_BLAS这个宏定义,并没有找到-DEIGEN_USE_BLAS这个宏定义.说明了blas特性并没有被启用.

   你想要把 eigen 作为 blas 的实现 还是要给 eigen提供 blas的实现
8. Sunrisepeak commented on Jun 29, 2026

   

   Sunrisepeak

   on Jun 29, 2026

   Member

   More actions

   最新mcpp版本已经支持 更强大的 feature机制, 可以xlings update mcpp -y更新到最新版本体验

   • feat(features): Feature System v2 — package-owned defines + capabilities (v0.0.69) #181
   • https://github.com/mcpp-community/mcpp/blob/main/docs/05-mcpp-toml.md#28-features--features-cargo-style-additive

   

   ---

   
9. Sunrisepeak

   closed this as completedon Jul 7, 2026
10. Sunrisepeak

    self-assigned this

    on Jul 7, 2026