[CMake] What are the best practices for project installation hierarchy?

[Egor Tensin]

Hello,

I'm bothered with my approach to `install`ing CMake-enabled project
components. The whole source tree is separated into "libs" and
"examples" subdirectories, with a lot of libraries under the "libs"
subdirectory and library usage examples under the "examples"
subdirectory.

For example:
.
├── examples
│   ├── CMakeLists.txt
│   ├── lib1
│   │   ├── CMakeLists.txt
│   │   ├── example1.cpp
│   │   └── example2.cpp
│   └── lib2
│       ├── CMakeLists.txt
│       └── example1.cpp
└── libs
    ├── CMakeLists.txt
    ├── lib1
    └── lib2

I would like to install the corresponding targets like this:

.
├── bin
│   └── examples
│       ├── lib1
│       │   ├── example1.exe
│       │   └── example2.exe
│       └── lib2
│           └── example1.exe
└── lib
    ├── lib1.lib
    └── lib2.lib

At the moment I'm just defining a custom variable (say,
INSTALL_PREFIX) in the highest-level CMakeLists.txt, and basically in
each of the underlying CMakeLists.txt files append something to the
variable. For example, in libs/CMakeLists.txt I use:

set(INSTALL_PREFIX "${INSTALL_PREFIX}/lib")

and in examples/CMakeLists.txt:

set(INSTALL_PREFIX "${INSTALL_PREFIX}/bin")

and in examples/lib1/CMakeLists.txt:

set(INSTALL_PREFIX "${INSTALL_PREFIX}/lib1")

I'm wondering if it's idiomatic, because at the moment I'm facing a
few issues using this approach. For example, if I build & install only
examples/lib1/example1.cpp, it gets installed to "lib1/" instead of
"bin/examples/lib1".

Could you please share your best practices on installing project
components or give me an advice on how to fix the issue(s) I'm facing?

Thank you,
Egor Tensin.