What is INSTALL_DIR useful for in ExternalProject_Add command?

Question

I don\'t understand the usage of INSTALL_DIR in ExternalProject_Add command. I try to use it but it does not seem to work. Here is an example of a CMakeLists.txt, using Eigen li

Answer 1

From what I found in this discussion https://www.mail-archive.com/cmake@cmake.org/msg51663.html (scroll to the end of the page to navigate through the thread messages) it is indeed pretty common thing to use CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=${CMAKE_BINARY_DIR}/contrib

Furthermore, lurking through the ExternalProject.cmake module I found out that the only effect setting this directory has is that CMake will create directory specified in INSTALL_DIR before doing anything else.

Also, it will set the property that you can gather through ExternalProject_Get_Property(${project_name} install_dir) command.

And that's pretty much it.

// As of CMake version 3.2.2