let us know version of cmake on your pc and version of cpprestsdk

let us know version of cmake on your pc and version of cpprestsdk

CMake 3.14
cpprestsdk: latest commit on master branch

my pc: cmake version 3.10.2
cpprest is boost-1.72.0

Using cmd as below to switch to boost-1.72.0
git reset --hard
git fetch
git checkout boost-1.72.0
git submodule update --init
cd boost/libs/asio
git checkout boost-1.69.0

I can cross compiler and push lib at https://github.com/letrthong/orangepi_zero_release/tree/master/x32 with toolchain gcc-linaro-arm-linux/gcc-linaro-7.3.1-2018.05-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-g++

Resolved by #1383?

Resolved by #1383?

Not quite. #1383 fixes only part of the problem: now Boost is searched for through the find_dependency macro calls, but it's still not present as a transitive dependency on the exported targets.

What I want to be able to do (taken directly from the project's README):

cmake_minimum_required(VERSION 3.9)
project(main)

find_package(cpprestsdk REQUIRED)

add_executable(main main.cpp)
target_link_libraries(main PRIVATE cpprestsdk::cpprest)

But this does not work. the cpprestsdk::cpprest imported target does not carry the transitive dependency on Boost::system and OpenSSL::crypto.

What I need to do now is:

cmake_minimum_required(VERSION 3.9)
project(main)

find_package(cpprestsdk REQUIRED)

add_executable(main main.cpp)
target_link_libraries(main PRIVATE cpprestsdk::cpprest Boost::system OpenSSL::Crypto)

The problem is that the targets imported by the calls to find_dependency in the package configuration file (Release/cmake/cpprestsdk-config.in.cmake) do not match the actual targets linked against in Release/src/CMakeLists.txt. The latter creates targets different from those created by the find_dependency macro, and are created by the cpprest_find_* wrapper macros in the Release/cmake/cpprest_find_*.cmake files.

For example, find_dependency(Boost COMPONENTS system date_time regex) uses the CMake supplied FindBoost module, which creates the following imported targets:

Boost::system
Boost::date_time
Boost::regex

But the macro cpprest_find_boost creates the target cpprestsdk_boost_internal, which is what added to the INTERFACE requirements of the cpprestsdk::cpprest target, which is ultimately exported in the package configuration file. The cpprestsdk_boost_internal target has itself transitive dependencies on the various discovered boost library components.

Now one would expect this would still work, (assuming that cprest_find_* and the find_dependency macros end up finding the same files and directories for the given library).
But the cpprest_find_boost creates the cpprestsdk_boost_internal target with a $<BUILD_INTERFACE:...> generator expression, which expands to the empty string when exported by install(EXPORT ...)

The problem described above also occurs with the other dependencies (zlib, openssl, etc)