Conan

How to create conan debug profile

Run this command to create a debug profile from your default profile:

cp ~/.conan/profiles/default ~/.conan/profiles/debug && sed -i -e 's/Release/Debug/g' ~/.conan/profiles/debug

Example output from conan profile show debug:

[settings]
os=Linux
os_build=Linux
arch=x86_64
arch_build=x86_64
compiler=gcc
compiler.version=9
compiler.libcxx=libstdc++
build_type=Debug
[options]
[conf]
[build_requires]
[env]

 

Posted by Uli Köhler in C/C++, Conan

How to list local conan packages

In order to list local conan packages, run

conan search

Example output:

$ conan search
Existing package recipes:

cpr/1.6.2
elasticlient/0.2
elasticlient/[email protected]/testing
gtest/cci.20210126
jsoncpp/1.9.4
libcurl/7.69.1
libcurl/7.78.0
openssl/1.1.1l
zlib/1.2.11

 

Posted by Uli Köhler in Conan

How to fix Conan CMake “Could NOT find OpenSSL”

Problem:

When building your conan package, you see this CMake error:

CMake Error at /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:146 (message):
  Could NOT find OpenSSL, try to set the path to OpenSSL root folder in the
  system variable OPENSSL_ROOT_DIR (missing: OPENSSL_CRYPTO_LIBRARY
  OPENSSL_INCLUDE_DIR)
Call Stack (most recent call first):
  /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:393 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake-3.16/Modules/FindOpenSSL.cmake:447 (find_package_handle_standard_args)
  ../_deps/curl-src/CMakeLists.txt:365 (find_package)

even though your conanfile.py declares OpenSSL as a dependency:

class MyPackageConan(ConanFile):
    # ...
    requires = ("openssl/1.1.1l", )

Solution:

Make sure that the project’s CMakeLists.txt contains these lines:

include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
conan_basic_setup()

Typically, the way to do this is to use this code which is automatically generated by conan new:

        # This small hack might be useful to guarantee proper /MT /MD linkage
        # in MSVC if the packaged project doesn't have variables to set it
        # properly
        tools.replace_in_file("hello/CMakeLists.txt", "PROJECT(HelloWorld)",
                              '''PROJECT(HelloWorld)
include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
conan_basic_setup()''')

in source() like this:

    def source(self):
        self.run("git clone https://github.com/conan-io/hello.git")
        # This small hack might be useful to guarantee proper /MT /MD linkage
        # in MSVC if the packaged project doesn't have variables to set it
        # properly
        tools.replace_in_file("hello/CMakeLists.txt", "PROJECT(HelloWorld)",
                              '''PROJECT(HelloWorld)
include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
conan_basic_setup()''')

Note that you need to replace both hello/CMakeLists.txt with the correct filename (typically, just replace hello by). Also, you need to replace both instances PROJECT(HelloWorld) by the actual line from your CMakeLists.txt in order for the replace command to work.

Posted by Uli Köhler in C/C++, CMake, Conan

How to add build-only dependencies in Conan recipe

Just add build_requires = ('dep1/version1', 'dep1/version2') to your conanfile.py:

class MyPackageConan(ConanFile):
    # ...
    requires = ("openssl/1.1.1l", )
    build_requires = ("jsoncpp/1.9.4", )

 

Posted by Uli Köhler in C/C++, Conan

How to run ‘git submodule update’ in Conan recipe

If you want to run git submodule update in your conanfile.py, you can simple add a self.run() command after the git clone command:

self.run("git clone https://github.com/conan-io/hello.git")
self.run("cd hello && git submodule update --init --recursive")

Full example:

self.run("git clone https://github.com/seznam/elasticlient.git -b version-0.2")
self.run("cd elasticlient && git submodule update --init --recursive")

Note that you need to cd <directory> && git submodule update

Posted by Uli Köhler in C/C++, Conan

How to add conan CMake build definition

When building a library using conan, this is the default conanfile.py definition for building using CMake

cmake = CMake(self)
cmake.configure(source_folder="hello")
cmake.build()

You can easily add definitions like this:

cmake.definitions["MY_FLAG"] = "1"

This will generate -DMY_FLAG=1 when calling CMake

Full example:

cmake = CMake(self)
cmake.definitions["USE_SYSTEM_CPR"] = "1
cmake.configure(source_folder="elasticlient")"
cmake.build()

Note that you need to add all cmake.definitions calls before calling cmake.configure()

Posted by Uli Köhler in C/C++, Conan