set(CMAKE_CXX_STANDARD 20) set(CMAKE_CXX_STANDARD_REQUIRED ON)
26
May
2023
Build systems
25
Apr
2023
How to fix SCons error: Do not know how to make File target `clean’
Problem:
You are trying to clean your SCons build using
scons clean
but you see the following error message:
scons: Reading SConscript files ... scons: done reading SConscript files. scons: Building targets ... scons: *** Do not know how to make File target `clean' (/home/user/myproject/clean). Stop. scons: building terminated because of errors.
Solution:
When using SCons, the correct command to clean is
scons --clean
25
Apr
2023
How to fix SCons not providing colored GCC/C++ output
You can force SCons to provide colored output when using GCC or G++ by adding
-fdiagnostics-color=always
to your CFLAGS or CXXFLAGS. Typically, my recommendation is to add it to both CFLAGS and CXXFLAGS.
25
Apr
2023
Minimal CMake .gitignore
# CMake generated files build/ CMakeCache.txt CMakeFiles/ Makefile cmake_install.cmake install_manifest.txt
08
Apr
2023
How to include current directory using CMake
It is often helpful to include the current directory for C++ projects. When using GCC directly, this can be done using -I., whereas for CMake you need to use the following statement:
target_include_directories(myexe PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})Remember to replace myexe by the name of your executable target.
07
Dec
2022
How to fix CMake Error: Cannot find source file: *.cpp
Problem:
You are trying to build your CMake-based project using a CMakeLists.txt like
cmake_minimum_required(VERSION 3.10) project(my_project) add_executable(my_project *.cpp)
Solution:
You can’t use the glob pattern *.cpp directly in add_executable(). You need to use file(GLOB ...) in order to set a variable, which you can then use in add_executable():
cmake_minimum_required(VERSION 3.10)
project(my_project)
file(GLOB SRC_FILES *.cpp)
add_executable(my_project ${SRC_FILES})
25
Nov
2022
How to fix CMake “target_include_directories called with invalid arguments”
Problem:
In your CMakeLists.txt, you want to add an include directory such as /usr/include/mylibrary for the executable myexe using code like:
target_include_directories( myexe /usr/include/mylib )
But when you try to configure the build using cmake . or make, you see an error message like
CMake Error at CMakeLists.txt:8 (target_include_directories): target_include_directories called with invalid arguments -- Configuring incomplete, errors occurred!
Solution:
You need to add PUBLIC between the target name (myexe) and the include directory/directories:
target_include_directories( myexe PUBLIC /usr/include/mylib )
12
Feb
2022
Conan .gitignore for executable projects
This is the .gitignore I use for most of my conan-built executable projects:
CMakeCache.txt CMakeFiles/ Makefile bin/ cmake_install.cmake conan.lock conanbuildinfo.cmake conanbuildinfo.txt conaninfo.txt graph_info.json
It is debatable whether you should include lock files such as conan.lock. My opinion is that in the development phase they should be ignored but reconsidered when entering into production service.
12
Feb
2022
How to initialize new C++ executable project using conan
In the directory where you want to create the project, run (obviously, replace mypackageby the name of everywhere in our code!)
conan new mypackage/1.0.0 -s
-s is important here. It tells conan that the source is available in the project directory and it should not be pulled using git etc.
This will initialize a shared library project, which we will now modify to build an executable.
First, open src/CMakeLists.txt and change add_library() to add_executable(), for example
add_library(mypackage mypackage.cpp)
to
add_executable(mypackage mypackage.cpp)
Now we shall modify conanfile.py to properly build & install the executable:
def package(self):
self.copy("*.h", dst="include", src="src")
self.copy("*.lib", dst="lib", keep_path=False)
self.copy("*.dll", dst="bin", keep_path=False)
self.copy("*.dylib*", dst="lib", keep_path=False)
self.copy("*.so", dst="lib", keep_path=False)
self.copy("*.a", dst="lib", keep_path=False)
def package_info(self):
self.cpp_info.libs = ["NoxecoDB"]
with
def package(self):
self.copy("mypackage", src="bin", dst="bin", keep_path=False)
def package_info(self):
self.env_info.PATH = os.path.join(self.package_folder, "bin")
def deploy(self):
self.copy("mypackage", dst="bin", src="bin")
and add
import os.path
to the top of the file
Now let’s add a main() function to src/mypackage.cpp. Replace the file’s content with
#include <iostream>
int main(int argc, char** argv) {
std::cout << "Hello World!" <<std::endl;
}
Now it’s time to install the dependencies & build the project using
conan install . && conan build .
The executable will be in
bin/mypackage
You can run it using
./bin/mypackage
which will print
Hello World!
I also recommend to add this .gitignore:
CMakeCache.txt CMakeFiles/ Makefile bin/ cmake_install.cmake conan.lock conanbuildinfo.cmake conanbuildinfo.txt conaninfo.txt graph_info.json
23
Jan
2022
How to fix conan install ERROR: Missing binary
Problem:
When running
conan install .
you see ERROR: Missing binary error messages like this:
Installing (downloading, building) binaries... ERROR: Missing binary: cpr/1.6.2:76fe60a9d5c829a2384b0f578695b5a6357b8acc ERROR: Missing binary: gtest/cci.20210126:c37dc23725d84483088a68c29e2dd7122c328359 ERROR: Missing binary: jsoncpp/1.9.4:718278bac9f92b77a9a44bfbe1aa00d1c8344d51 ERROR: Missing binary: libcurl/7.78.0:d287dc966931230205222ceabf47400733e72fa3 ERROR: Missing binary: openssl/1.1.1l:c3baf9fae083edda2e0c5ef3337b6a111016a898 ERROR: Missing binary: zlib/1.2.11:c3baf9fae083edda2e0c5ef3337b6a111016a898
Solution:
Use the --build=missing flag for conan install to enable building the dependencies for which no binaries are available:
conan install . --build=missing
Complete error log example
Configuration:
[settings]
arch=armv8
arch_build=armv8
build_type=Release
compiler=gcc
compiler.libcxx=libstdc++
compiler.version=9
os=Linux
os_build=Linux
[options]
[build_requires]
[env]
openssl/1.1.1l: Not found in local cache, looking in remotes...
openssl/1.1.1l: Trying with 'conancenter'...
Downloading conanmanifest.txt completed [0.26k]
Downloading conanfile.py completed [40.47k]
Downloading conan_export.tgz completed [0.25k]
Decompressing conan_export.tgz completed [0.00k]
openssl/1.1.1l: Downloaded recipe revision 0
cpr/1.6.2: Not found in local cache, looking in remotes...
cpr/1.6.2: Trying with 'conancenter'...
Downloading conanmanifest.txt completed [0.25k]
Downloading conanfile.py completed [9.62k]
Downloading conan_export.tgz completed [0.30k]
Decompressing conan_export.tgz completed [0.00k]
cpr/1.6.2: Downloaded recipe revision 0
WARN: cpr/1.6.2: requirement libcurl/7.80.0 overridden by elasticlient/0.2 to libcurl/7.78.0
libcurl/7.78.0: Not found in local cache, looking in remotes...
libcurl/7.78.0: Trying with 'conancenter'...
Downloading conanmanifest.txt completed [0.70k]
Downloading conanfile.py completed [27.11k]
Downloading conan_export.tgz completed [0.23k]
Decompressing conan_export.tgz completed [0.00k]
libcurl/7.78.0: Downloaded recipe revision 0
jsoncpp/1.9.4: Not found in local cache, looking in remotes...
jsoncpp/1.9.4: Trying with 'conancenter'...
Downloading conanmanifest.txt completed [0.65k]
Downloading conanfile.py completed [4.90k]
Downloading conan_export.tgz completed [0.25k]
Decompressing conan_export.tgz completed [0.00k]
jsoncpp/1.9.4: Downloaded recipe revision 0
gtest/cci.20210126: Not found in local cache, looking in remotes...
gtest/cci.20210126: Trying with 'conancenter'...
Downloading conanmanifest.txt completed [0.39k]
Downloading conanfile.py completed [8.14k]
Downloading conan_export.tgz completed [0.32k]
Decompressing conan_export.tgz completed [0.00k]
gtest/cci.20210126: Downloaded recipe revision 0
conanfile.py (elasticlient/0.2): Installing package
Requirements
cpr/1.6.2 from 'conancenter' - Downloaded
jsoncpp/1.9.4 from 'conancenter' - Downloaded
libcurl/7.78.0 from 'conancenter' - Downloaded
openssl/1.1.1l from 'conancenter' - Downloaded
zlib/1.2.11 from 'conancenter' - Cache
Packages
cpr/1.6.2:76fe60a9d5c829a2384b0f578695b5a6357b8acc - Missing
jsoncpp/1.9.4:718278bac9f92b77a9a44bfbe1aa00d1c8344d51 - Missing
libcurl/7.78.0:d287dc966931230205222ceabf47400733e72fa3 - Missing
openssl/1.1.1l:c3baf9fae083edda2e0c5ef3337b6a111016a898 - Missing
zlib/1.2.11:c3baf9fae083edda2e0c5ef3337b6a111016a898 - Missing
Build requirements
gtest/cci.20210126 from 'conancenter' - Downloaded
Build requirements packages
gtest/cci.20210126:c37dc23725d84483088a68c29e2dd7122c328359 - Missing
Installing (downloading, building) binaries...
ERROR: Missing binary: cpr/1.6.2:76fe60a9d5c829a2384b0f578695b5a6357b8acc
ERROR: Missing binary: gtest/cci.20210126:c37dc23725d84483088a68c29e2dd7122c328359
ERROR: Missing binary: jsoncpp/1.9.4:718278bac9f92b77a9a44bfbe1aa00d1c8344d51
ERROR: Missing binary: libcurl/7.78.0:d287dc966931230205222ceabf47400733e72fa3
ERROR: Missing binary: openssl/1.1.1l:c3baf9fae083edda2e0c5ef3337b6a111016a898
ERROR: Missing binary: zlib/1.2.11:c3baf9fae083edda2e0c5ef3337b6a111016a898
07
Sep
2021
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]
04
Sep
2021
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
02
Sep
2021
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.
02
Sep
2021
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", )
02
Sep
2021
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
02
Sep
2021
How to generate new Conan recipe for pre-existing package
If you want to create a new conan build recipe for a package that already exists, use
Without tests:
conan new hello/0.1
With tests:
conan new hello/0.1 -t
More info: See packaging docs
02
Sep
2021
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()
02
Sep
2021
How to fix CMake Protobuf “FindThreads only works if either C or CXX language is enabled”
Problem:
When trying to configure your CMake project using
find_package(Protobuf REQUIRED)
you see an error message like
CMake Error at /usr/share/cmake-3.16/Modules/FindThreads.cmake:49 (message): FindThreads only works if either C or CXX language is enabled Call Stack (most recent call first): /usr/share/cmake-3.16/Modules/FindProtobuf.cmake:420 (find_package) CMakeLists.txt:7 (find_package) -- Configuring incomplete, errors occurred!
Solution:
You need to put your
project(MyProject)
line before the
find_package(Protobuf REQUIRED)
line. If you don’t have a project() line, create one.
08
Jul
2021
How to compile boost unit test program using CMake
Add this to your CMakeLists.txt:
#
# Compile test suite
#
find_package(Boost COMPONENTS system filesystem unit_test_framework REQUIRED)
add_executable(test_myprogram
tests/MyTest.cpp
)
target_include_directories(test_myprogram PUBLIC "${CMAKE_CURRENT_LIST_DIR}/include")
target_compile_features(test_myprogram PRIVATE cxx_std_17)
target_link_libraries(test_myprogram
${Boost_FILESYSTEM_LIBRARY}
${Boost_SYSTEM_LIBRARY}
${Boost_UNIT_TEST_FRAMEWORK_LIBRARY}
)
add_test(test_myprogram test_myprogram)
# make "make test" run the test program
add_custom_target(test
DEPENDS myprogram
COMMAND ./test_myprogram
)In order to build the program and the test, run
make
In order to run the tests, use
make test
08
Jul
2021
How to fix CMake error Could not find a package configuration file provided by “boost_unit_test_framework”
Problem:
When compiling your CMake-based C++
CMake Error at /usr/lib/x86_64-linux-gnu/cmake/Boost-1.71.0/BoostConfig.cmake:117 (find_package):
Could not find a package configuration file provided by
"boost_unit_test_framework" (requested version 1.71.0) with any of the
following names:
boost_unit_test_frameworkConfig.cmake
boost_unit_test_framework-config.cmake
Add the installation prefix of "boost_unit_test_framework" to
CMAKE_PREFIX_PATH or set "boost_unit_test_framework_DIR" to a directory
containing one of the above files. If "boost_unit_test_framework" provides
a separate development package or SDK, be sure it has been installed.
Call Stack (most recent call first):
/usr/lib/x86_64-linux-gnu/cmake/Boost-1.71.0/BoostConfig.cmake:182 (boost_find_component)
/usr/share/cmake-3.16/Modules/FindBoost.cmake:443 (find_package)
OCCUtils/CMakeLists.txt:58 (find_package)
-- Configuring incomplete, errors occurred!
Solution:
The error message is trying to tell you that you don’t have the boost unit test library installed (or CMake can’t find it).
On Ubuntu, for example, install it using
sudo apt -y install libboost-test-dev
On Windows you can install it using the prebuilt boost binaries for Windows.