qbs cannot find the output of submodule (build with cmake) - cmake

Question

I have a submodule built by cmake and successully build it in qbs script (see below code).
Product {
name: "mylib"
type: ["staticlibrary"]
// define buildScript, outputPath, libPrefix, libExt, cmakeBuildType, cmakeBuildConfig
// Note that outputPath is inside mylib folder, not qbs's build directory
Rule {
multiplex: true
outputArtifacts: [
{
filePath: product.outputPath + product.libPrefix + "lib1static" + product.libExt,
fileTags: ["staticlibrary"]
},
{
filePath: product.outputPath + product.libPrefix + "lib2static" + product.libExt,
fileTags: ["staticlibrary"]
}
]
outputFileTags: ["staticlibrary"]
prepare: {
var cmd = new Command(product.buildScript, [product.outputPath, product.cmakeBuildType, product.cmakeBuildConfig]);
cmd.description = "cmake generate mylib";
cmd.workingDirectory = product.sourceDirectory + "/mylib/build_cmake";
return [cmd];
}
}
However, sometimes qbs delete the "lib1static" and "lib2static" and I get this error while linking:
clang: error: no such file or directory: '<path>/lib1static.a'
clang: error: no such file or directory: '<path>/lib2static.a'
I tried to debug but still don't know why. The first build can be successful with all output libraries are built, but in the next build, all libraries are disappeared.
Can anyone here explain and tell me which is the best practice for this case?

Answer 1

I don't see why the files would get deleted. However, there is another problem:
The rule as shown above will only run once, because it has no inputs, so changes in the source files of your sub-project will not get picked up.
(And, as a side note: If the outputs are not "dynamic", you can declare Artifact items, rather than using the outputArtifacts and outputFileTags properties.)
Try this:
Rule {
multiplex: true
alwaysRun: true
Artifact {
filePath: product.outputPath + product.libPrefix + "lib1static" + product.libExt
fileTags: ["staticlibrary"]
alwaysUpdated: false
}
Artifact {
filePath: product.outputPath + product.libPrefix + "lib2static" + product.libExt
fileTags: ["staticlibrary"]
alwaysUpdated: false
}
prepare: {
var cmd = new Command(product.buildScript, [product.outputPath, product.cmakeBuildType, product.cmakeBuildConfig]);
cmd.description = "cmake generate mylib";
cmd.workingDirectory = product.sourceDirectory + "/mylib/build_cmake";
return [cmd];
}
}