尝试在 CMake 项目中使用 Boost Multi precision 时，未定义对 mpfr_*() 函数的引用？

Question

我想在我的 C++ 项目中使用 Boost Multi precision，但我无法做到。我怀疑我没有在我的根

CMakeLists.txt

配置中添加正确的依赖项，其相关部分如下所示：

cmake_minimum_required(VERSION 3.30.0)
project(MyProject VERSION 1.0.0 LANGUAGES C CXX)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_subdirectory(src)
add_subdirectory(app)
add_subdirectory(test)

find_package(Boost REQUIRED)
include_directories(${Boost_INCLUDE_DIRS})

list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
find_package(MPFR REQUIRED)
include_directories(${MPFR_INCLUDE_DIRS})

set(CPACK_PROJECT_NAME ${PROJECT_NAME})
set(CPACK_PROJECT_VERSION ${PROJECT_VERSION})
include(CPack)

我确保在

app/CMakeLists.txt

中链接我的可执行文件的库：

add_executable(main main.cpp)
target_link_libraries(main PRIVATE myLib)
target_link_libraries(main ${Boost_LIBRARIES})
target_link_libraries(main ${MPFR_LIBRARIES})

以及我的图书馆

src/CMakeLists.txt

：

file(GLOB HEADER_LIST CONFIGURE_DEPENDS "${MyProject_SOURCE_DIR}/include/*.h")
add_library(myLib SomeFile.cpp ${HEADER_LIST})
target_include_directories(myLib PUBLIC ../include)
target_link_libraries(myLib ${Boost_LIBRARIES})
target_link_libraries(myLib ${MPFR_LIBRARIES})

我已经通过包管理器验证了

Boost

和

MPFR

都安装在我的系统上。 当我包含必要的标头并使用多精度类型时，我的 linter (

Clangd

) 不会产生错误：

#include <boost/multiprecision/mpfr.hpp>
// ...

int main() {
    IOParser<boost::multiprecision::mpfr_float_100> parser;
    // ...
}

但是当我编译程序时，我得到了一些对各种 MPFR 函数的未定义引用，例如：

[build] /usr/bin/ld: CMakeFiles/main.dir/main.cpp.o: in function `boost::multiprecision::backends::detail::mpfr_float_imp<100u, (boost::multiprecision::mpfr_allocation_type)1>::operator=(boost::multiprecision::backends::detail::mpfr_float_imp<100u, (boost::multiprecision::mpfr_allocation_type)1>&&) [clone .isra.0]':
[build] main.cpp:(.text+0x2dc): undefined reference to `mpfr_swap'
[build] /usr/bin/ld: main.cpp:(.text+0x30c): undefined reference to `mpfr_set4'
[build] /usr/bin/ld: main.cpp:(.text+0x386): undefined reference to `mpfr_init2'

我做错了什么？

Answer 1

离开不完整的旧问题和github搜索我总结如下：

MPFR (https://www.mpfr.org/) 不提供 CMake 支持。

所以你需要从其他地方获取FindMPFR。如果您的发行版打包程序没有添加它，您必须将其发送到您自己的存储库中：

(mkdir -pv cmake && cd cmake && wget -c https://raw.githubusercontent.com/quarkslab/NFLlib/refs/heads/master/cmake/FindMPFR.cmake)

下载以下示例

cmake/FindMPFR.cmake

：

# Copyright (c) 2008-2010 Kent State University
# Copyright (c) 2011-2012 Texas A&M University
#
# This file is distributed under the MIT License. See the accompanying file
# LICENSE.txt or http://www.opensource.org/licenses/mit-license.php for terms
# and conditions.

# FIXME: How do I find the version of MPFR that I want to use?
# What versions are available?

# NOTE: MPFR prefix is understood to be the path to the root of the MPFR
# installation library.
set(MPFR_PREFIX "" CACHE PATH "The path to the previx of an MPFR installation")

find_path(MPFR_INCLUDE_DIR mpfr.h
PATHS ${MPFR_PREFIX}/include /usr/include /usr/local/include)

find_library(MPFR_LIBRARY NAMES mpfr
PATHS ${MPFR_PREFIX}/lib /usr/lib /usr/local/lib)

if(MPFR_INCLUDE_DIR AND MPFR_LIBRARY)
get_filename_component(MPFR_LIBRARY_DIR ${MPFR_LIBRARY} PATH)
set(MPFR_FOUND TRUE)
endif()


if(MPFR_FOUND)
if(NOT MPFR_FIND_QUIETLY)
MESSAGE(STATUS "Found MPFR: ${MPFR_LIBRARY}")
endif()
elseif(MPFR_FOUND)
if(MPFR_FIND_REQUIRED)
message(FATAL_ERROR "Could not find MPFR")
endif()
endif()

现在，您可以将 cmake 目录添加到前缀路径：

set(CMAKE_PREFIX_PATH "${CMAKE_SOURCE_DIR}/cmake:${CMAKE_PREFIX_PATH}")

或者，显然您已经使用的模块路径行：

list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")

现在我这样做是为了 MPFR 和 GMP 更加完整：

• 文件

  ./main.cpp

   #include <boost/multiprecision/mpfr.hpp>
   #include <boost/multiprecision/gmp.hpp>
  
   #include <iostream>
  
  
   int main()
   {
       using namespace boost::multiprecision;
  
       mpfr_float_100 a = 1.0;
       mpfr_float_100 b = 2.0;
       mpfr_float_100 c = a + b;
  
       std::cout << c << std::endl;
  
       mpz_int d = 1;
       mpz_int e = 1;
       mpz_int f = d + e;
  
       std::cout << f << std::endl;
  
       return 0;
   }
  

• 空文件

  ./app/CMakeLists.txt

• 空文件

  ./test/CMakeLists.txt

• 空文件

  ./SomeFile.cpp

• 空文件

  ./src/CMakeLists.txt

• 文件

  ./CMakeLists.txt

   cmake_minimum_required(VERSION 3.29.0)
   project(MyProject VERSION 1.0.0 LANGUAGES C CXX)
   #set(CMAKE_PREFIX_PATH "${CMAKE_SOURCE_DIR}/cmake:${CMAKE_PREFIX_PATH}")
   set(CMAKE_CXX_STANDARD 20)
   set(CMAKE_CXX_STANDARD_REQUIRED ON)
  
   find_package(Boost REQUIRED)
   include_directories(${Boost_INCLUDE_DIRS})
  
   list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
   find_package(MPFR REQUIRED)
   include_directories(${MPFR_INCLUDE_DIRS})
  
   find_package(GMP REQUIRED)
   include_directories(${GMP_INCLUDE_DIRS})
  
   add_subdirectory(app)
   add_subdirectory(test)
  
   set(CPACK_PROJECT_NAME ${PROJECT_NAME})
   set(CPACK_PROJECT_VERSION ${PROJECT_VERSION})
   include(CPack)
  
   add_executable(main main.cpp)
   target_link_libraries(main PRIVATE myLib)
   target_link_libraries(main PUBLIC ${Boost_LIBRARIES})
   target_link_libraries(main PUBLIC ${MPFR_LIBRARY})
   target_link_libraries(main PUBLIC ${GMP_LIBRARY})
  
   file(GLOB HEADER_LIST CONFIGURE_DEPENDS "${MyProject_SOURCE_DIR}/include/*.h")
   add_library(myLib SomeFile.cpp ${HEADER_LIST})
   target_include_directories(myLib PUBLIC ../include)
   target_link_libraries(myLib ${Boost_LIBRARIES})
   target_link_libraries(myLib ${MPFR_LIBRARIES})
  

• 文件

  ./cmake/FindMPFR.cmake

   # Copyright (c) 2008-2010 Kent State University
   # Copyright (c) 2011-2012 Texas A&M University
   #
   # This file is distributed under the MIT License. See the accompanying file
   # LICENSE.txt or http://www.opensource.org/licenses/mit-license.php for terms
   # and conditions.
  
   # FIXME: How do I find the version of MPFR that I want to use?
   # What versions are available?
  
   # NOTE: MPFR prefix is understood to be the path to the root of the MPFR
   # installation library.
   set(MPFR_PREFIX "" CACHE PATH "The path to the previx of an MPFR installation")
  
   find_path(MPFR_INCLUDE_DIR mpfr.h
   PATHS ${MPFR_PREFIX}/include /usr/include /usr/local/include)
  
   find_library(MPFR_LIBRARY NAMES mpfr
   PATHS ${MPFR_PREFIX}/lib /usr/lib /usr/local/lib)
  
   if(MPFR_INCLUDE_DIR AND MPFR_LIBRARY)
   get_filename_component(MPFR_LIBRARY_DIR ${MPFR_LIBRARY} PATH)
   set(MPFR_FOUND TRUE)
   endif()
  
  
   if(MPFR_FOUND)
   if(NOT MPFR_FIND_QUIETLY)
   MESSAGE(STATUS "Found MPFR: ${MPFR_LIBRARY}")
   endif()
   elseif(MPFR_FOUND)
   if(MPFR_FIND_REQUIRED)
   message(FATAL_ERROR "Could not find MPFR")
   endif()
   endif()
  

• 文件

  ./cmake/FindGMP.cmake

   # Copyright (c) 2008-2010 Kent State University
   # Copyright (c) 2011-2012 Texas A&M University
   #
   # This file is distributed under the MIT License. See the accompanying file
   # LICENSE.txt or http://www.opensource.org/licenses/mit-license.php for terms
   # and conditions.
  
   # FIXME: How do I find the version of GMP that I want to use?
   # What versions are available?
  
   # NOTE: GMP prefix is understood to be the path to the root of the GMP
   # installation library.
   set(GMP_PREFIX "" CACHE PATH "The path to the prefix of a GMP installation")
  
  
   find_path(GMP_INCLUDE_DIR gmp.h
   PATHS ${GMP_PREFIX}/include /usr/include /usr/local/include)
  
   find_library(GMP_LIBRARY NAMES gmp
   PATHS ${GMP_PREFIX}/lib /usr/lib /usr/local/lib)
  
  
   if(GMP_INCLUDE_DIR AND GMP_LIBRARY)
   get_filename_component(GMP_LIBRARY_DIR ${GMP_LIBRARY} PATH)
   set(GMP_FOUND TRUE)
   endif()
  
   if(GMP_FOUND)
   if(NOT GMP_FIND_QUIETLY)
   MESSAGE(STATUS "Found GMP: ${GMP_LIBRARY}")
   endif()
   elseif(GMP_FOUND)
   if(GMP_FIND_REQUIRED)
   message(FATAL_ERROR "Could not find GMP")
   endif()
   endif()
  

它可以在我的机器（TM）上使用 Nix 软件包用于

mpfr

和

gmp

：