Installation behavior of shared versus static libraries

[ben.boeckel (Ben Boeckel (Kitware))]

@neuroevolutus

I am wondering why making a shared library would cause it to install once and show as up-to-date on subsequent invocations of cmake --install whereas using the default library type (which is ostensibly STATIC on my system) would cause it to have to be installed regardless of whether cmake --install had already been invoked.

The default library type is controlled by BUILD_SHARED_LIBS (usually a cache variable). Anyways, I would check the cmake_install.cmake code for each; there may be some difference here?

@neuroevolutus

Additionally, given the details from the context above, I would like to know why turning my library into a shared library would cause a dependent target executable to repeatedly install on each invocation of cmake --install whereas using a static library would cause the dependent executable to install only once.

On macOS, there is some binary patching to fixup rpath entries between the build and install tree. This may tinker with byte-exact files and cause a “new” install to happen.