Using a standalone asio for crow with CPM

[rhvarrier]

Hello all

I want to build a standalone app using CPM to manage the dependecies. I see that Crow depends on asio and it seems that it I need to install libasio-dev in order use Crow.

There a way to force Crow to use a version of asio that I downloded using CPM. I see that in Crow Cmake file, there is a find_package for asio and that there is Findasio.cmake that does the follwing find_path(ASIO_INCLUDE_DIR asio.hpp)

I tried setting asio_ROOT as suggested by the cmake documentation

cmake_minimum_required(VERSION 3.20)

project(app VERSION 0.1 LANGUAGES CXX)

include(cmake/get_cpm.cmake)

find_package(Threads REQUIRED)
CPMAddPackage("gh:chriskohlhoff/asio#asio-1-32-0@1.32.0")

if(asio_ADDED)
  set(asio_ROOT ${asio_SOURCE_DIR}/asio/include)
  CPMAddPackage(Crow
  VERSION 1.2.0
  GITHUB_REPOSITORY CrowCpp/Crow
  OPTIONS
  "CROW_BUILD_EXAMPLES Off"
  "CROW_BUILD_TOOLS Off"
  "CROW_BUILD_TESTS Off"
  "CROW_BUILD_DOCS Off"
  "CROW_ENABLE_COMPRESSION Off"
  "CROW_ENABLE_SSL Off"
)
else()
  message(ERROR "Asio not found")
endif()

set(BIN_OUT app)
file(
     GLOB_RECURSE
     SRCS
     src/*
    )
add_executable(${BIN_OUT} ${SRCS})
target_link_libraries(${BIN_OUT} 
                      Crow::Crow)

But it does not work.

Is there a way to override this so that I can pass a path where asio is installed

[debugmenot]

its not required to actually install asio as a package. you can just download tgz, unpack it to build/_deps or someehere else and specify the path to asio include dir:

CPMAddPackage(
    GITHUB_REPOSITORY CrowCpp/Crow
    GIT_TAG v1.2.0 
    OPTIONS
        BUILD_SHARED_LIBS=OFF
        ASIO_INCLUDE_DIR=/usr/local/include # or ${ASIO_INCLUDE_DIR} that is valid after asio standalone tgz unpacking
)

and seems the problem is not there. Use asio with tag asio-1-30-2. Crowcpp for now is not compatible with latest asio build because of asio::io_service deprecation (should be replaced to asio::io_context)