Gradle c++ plugin - shared library linking

Help/Discuss
1

Hi

I’m building a project which has 2 sub projects: 1 shared lib and 1 exe.
The exe build.gradle has the following line:
lib project: “:lib_project”, library: “lib”, linkage: "static"
Each sub project has its own build.gradle.

I’m building on Windows 7.
When I run an install task on the exe project, the library project DLL isn’t installed in the install directory.
When I tried to change linkage to “shared” the link step fails, because lib.lib is missing.

Any ideas as to what I’m doing wrong?

Thanks

2

I’m now trying to add my own tasks to the exe project to copy the shared lib artifacts when the exe project install tassks are called.
However I can’t access any of the tasks in the native plugin.

E.g. Adding the following code to the exe build.gradle causes a build error:

task installLibrary << {
println(“installLibrary”)
} // end of task installAplLibrary

tasks.installX64DebugExeExecutable.dependsOn installAplLibrary

I get:
“Could not find property ‘installX64DebugExeExecutable’ on task set”

Any idea on how to access tasks in the native c++ plugin?

Thanks

3

Have you taken a look at the multi-project native sample in the Gradle distribution? The install task should be copying the shared object library if it’s needed. Sample project: https://github.com/gradle/gradle/tree/master/subprojects/docs/src/samples/native-binaries/multi-project

The reason you can’t access the tasks is that they are created on demand based on which variant of the library/executable is being built.

4

Yes I’ve taken a look at the multi project sample. I’m now changing my project to match.
However what I want is the ability to have a multi project setup, where each component has it’s build.gradle.

The current multi project setup is not scale-able in my opinion.

It’s good for a limited number of components, but it becomes messy if you have multiple libraries and multiple apps, where each client depends on a some of the libraries. You will end up with a very large build.gradle file that will hold all the data for all the projects. This will become harder and harder to maintain as the number of projects increases.

I think it would be better to have the components of a build.gradle based not just of the contents in that file, but also in any project file it depends on.

One more suggestion - add some tasks (even empty ones) that will allow hooking additional tasks that do custom build steps.
E.g.

  1. Add a preBuild task that will allow code generation tasks.
  2. Add a postBuild task that will allow some custom tests, or file copies
  3. preInstall and postInstall …

Thanks

5

I created a plugin that solves the issue in this thread see:
https://plugins.gradle.org/plugin/com.xykivo.nativeextension

It add pre/post compile/link/install tasks and tasks to copy shared library dependencies to the install executable output dir.