CMake config scripts installed in non-standard location on MS Windows

[gdkessler]

In the 1.7.4 version, the CMake config scripts (e.g. PocoConfig.cmake) are installed in "lib/cmake/Poco", which is not one of the default prefix paths used, by default, when find_package(Poco) is invoked (see https://cmake.org/cmake/help/v3.7/command/find_package.html), although it is one of the default prefix paths use to find the scripts on Unix. For MS Windows, an alternative location that will be looked at by find_package() would be a "cmake" directory. Ex:

if (WIN32)
    set(_CMAKE_INSTALL_DIR "cmake")
else ()
    set(_CMAKE_INSTALL_DIR "lib/cmake/${PROJECT_NAME}")
endif ()
install(
    FILES
        ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}/${PROJECT_NAME}Config.cmake
        ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}/${PROJECT_NAME}ConfigVersion.cmake
    DESTINATION
        "${_CMAKE_INSTALL_DIR}"
    COMPONENT
        Devel
)

Using a non-standard location for the Poco CMake script causes problems when packages are installed in a common location.

[bachp]

I actually think it's bad from CMake side to not have a common location that works on all platforms.
But I agree in this case we should change it as you proposed.

Could you submit a PR for this?

[gdkessler]

I completely agree that it is bad that the CMake find_package default search path does not have a common location that works on all platforms.

I would be happy to submit a PR with the modification I suggested above.

[gocarlos]

is this fixed?

[aleks-f]

i don't think it is in 1.x, develop probably. @Bjoe would know details

[zosrothko]

FYI, the installation directory for Poco with 32 arch should be in C:\Program Files (x86)\Poco\<vsversion>
and for the 64 arch in C:\Program Files\Poco\<vsversion> where <vsversion> should be "VSYYYY" because a user can decide to install poco-1.X on a single machine with VS2008, VS2010, VS2012, VS2015, VS2017

[gdkessler]

I would note that the issue here is where the cmake configuration scripts are installed within the main installation directory for Poco, not where the main installation directory is set to. I would also caution against hard-coding the installation directory, even though the default that cmake uses might not be able to disambiguate between compiler versions. In general, choosing the installation directory is handled in the installation-specific configuration step, and not providing an installation directory has a well-understood default. It should always be possible to override the installation directory with the CMAKE_INSTALL_PREFIX. If a user decides to use subdirectories to be able to install VS2008, VS2010, VS2012, VS2015, and VS2017 versions in C:\Program Files\Poco<vsversion> and C:\Program Files (x86)\Poco<vsversion>, then that can be done by setting the CMAKE_INSTALL_PREFIX appropriately for each compiler version and architecture. If the proposal is to have an installation script outside of the CMake script do just that, then that sounds good to me. I just wanted to suggest that a direct use of the CMake script to build one instance of the library should follow the expected CMake behavior in terms of installation. Thanks.

[Bjoe]

@aleks-f Well the #1454 fix is merged into develop not in 1.x
@gdkessler Hm, sorry I didn't get you, It is possible to set CMAKE_INSTALL_PREFIX ....

[gocarlos]

Eventually related: pocoproject/conan-poco#49