Native C++ third part library header files without extension

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1

Hi,

I am trying to include a third-party library (named “Eigen”) in a project using gradle. However, Eigen’s interface headers are organized in several level deep tree with the upper levels headers not having .h extensions. I can recursively search the tree and add all the directories, but I couldn’t figure out how to handle the extensionless headers. Here is a subset of the structure of Eigen:

Eigen/
├── Array
├── Cholesky
├── Dense
…
├── src
│ ├── Cholesky
│ │ ├── LDLT.h
│ │ ├── LLT.h
│ │ └── LLT_MKL.h

The top-level files e.g. Eigen/Array, Eigen/Dense etc. are what is typically used in #include statements, but are ignored by gradle. Here is a build.gradle snippet that tried to add the top-level as exportedHeaders:

model {
    components {
        eigen(NativeLibrarySpec) {
            sources.cpp {
                exportedHeaders {
                    srcDir "Eigen"
                    include "**/*"
                }
            }
        }
        stellarEvolution(NativeLibrarySpec) {
            sources.cpp {
                lib library: "alglib"
                source {
                    srcDir "StellarEvolution"
                    include "**/*.cpp"
                }
                exportedHeaders {
                    srcDir "StellarEvolution"
                }
            }
        }
    }
}

This, however, does not result in the Eigen directory added to the header search path when compiling StellarEvolution. I based my build.gradle on: gradle-3.1/samples/native-binaries/cpp, which seems to work, hence my assumption that the extension free header files are the problem.

I tried to find examples of how to do this but failed. Could someone help?

2

Nevermind. I was mis-understanding how exportedHeaders are processed. I was assuming that the headers are somehowe added to the build, along with a search path to all compilations which depend on the library. Instead, only the directory specified by exportedHeaders.srcDir is added to the search path and nothing is added to the build.

3

Hi Kaloyan,

You are correct. Only the directories are used for the source of exportedHeaders. Those directories are used as include root for the compiler.

Daniel