Visual Studio 2017 不链接库

Posted 2023-02-22

【中文标题】Visual Studio 2017 不链接库

【英文标题】：Visual Studio 2017 doesn't link the library

【发布时间】：2021-09-02 05:53:35

【问题描述】：

我正在尝试在 Visual Studio 2017 中构建一个简单的 C++ 程序。我在 Linux 上执行此操作时没有遇到任何问题，但由于某种原因它无法在 Windows 上运行。

这是程序：

// CMakeProject1.cpp : Defines the entry point for the application.
//

#include "CMakeProject1.h"
#include "fmt/core.h"
#include "fmt/xchar.h"
#include "spdlog/sinks/win_eventlog_sink.h"
#include "spdlog/sinks/msvc_sink.h"
#include "spdlog/sinks/wincolor_sink.h"
#include "spdlog/spdlog.h"
#include <exception>
#include <vector>

int main()


    std::vector<spdlog::sink_ptr> sinks;
    
    sinks.push_back(std::make_shared<spdlog::sinks::win_eventlog_sink_mt>("me"));

    sinks.push_back(std::make_shared<spdlog::sinks::msvc_sink_mt>());
    sinks.push_back(std::make_shared<spdlog::sinks::wincolor_stdout_sink_mt>());
    auto logger = std::make_shared<spdlog::logger>("main-logger", begin(sinks), end(sinks));

    SPDLOG_LOGGER_CALL(logger, spdlog::level::info, L"", L"Hello World!");

    return 0;

这是我的 CMakeLists.txt

# CMakeList.txt : Top-level CMake project file, do global configuration
# and include sub-projects here.
#
cmake_minimum_required(VERSION 3.20)

get_filename_component(Project $CMAKE_CURRENT_SOURCE_DIR NAME)
string(REPLACE " " "-" Project $Project)
project($Project CXX C)

set(CMAKE_VERBOSE_MAKEFILE ON)

include(FetchContent)

FetchContent_Declare(
    fmt
    GIT_REPOSITORY https://github.com/fmtlib/fmt.git
    GIT_TAG        8.0.1 
    )
FetchContent_MakeAvailable(fmt)
if (NOT fmt_POPULATED)
    FetchContent_Populate(fmt)
    add_subdirectory($fmt_SOURCE_DIR $fmt_BINARY_DIR)
endif()
message(STATUS "fmt_SOURCE_DIR = $fmt_SOURCE_DIR")
message(STATUS "fmt_BINARY_DIR = $fmt_BINARY_DIR")

FetchContent_Declare(
    spdlog
    GIT_REPOSITORY https://github.com/gabime/spdlog.git
    GIT_TAG        v1.9.2
    )
FetchContent_MakeAvailable(spdlog)
if (NOT spdlog_POPULATED)
    FetchContent_Populate(spdlog)
    set(SPDLOG_BUILD_EXAMPLES OFF)
    set(SPDLOG_BUILD_BENCH    OFF)
    set(SPDLOG_BUILD_TESTS    OFF)
    add_subdirectory($spdlog_SOURCE_DIR $spdlog_BINARY_DIR)
endif()
message(STATUS "spdlog_SOURCE_DIR = $spdlog_SOURCE_DIR")
message(STATUS "spdlog_BINARY_DIR = $spdlog_BINARY_DIR")

set(SourceDir $CMAKE_CURRENT_SOURCE_DIR)
set(ExecutableSources $SourceDir/main.cpp)
set(LinkLibraries fmt::fmt spdlog::spdlog)

set(Executable $Project)

message(STATUS CMAKE_VERSION = $CMAKE_VERSION)
message(STATUS LinkLibraries = $LinkLibraries)

add_executable($Executable $ExecutableSources)
add_definitions(-DSPDLOG_WCHAR_TO_UTF8_SUPPORT)
target_compile_options($Executable PUBLIC $CompilationFlags)
target_link_libraries($Executable PUBLIC $LinkLibraries)

生成构建文件的方式与在 Linux 上的方式相同

mkdir build
cd build
cmake ..

然后我在 Visual Studio 2017 中打开解决方案并构建它。但是我收到以下错误：

4>main.cpp
4>main.obj : error LNK2019: unresolved external symbol "void __cdecl spdlog::details::os::wstr_to_utf8buf(class fmt::v8::basic_string_view<wchar_t>,class fmt::v8::basic_memory_buffer<char,250,class std::allocator<char> > &)" (?wstr_to_utf8buf@os@details@spdlog@@YAXV?$basic_string_view@_W@v8@fmt@@AAV?$basic_memory_buffer@D$0PK@V?$allocator@D@std@@@56@@Z) referenced in function "protected: void __thiscall spdlog::logger::log_<wchar_t const (&)[13]>(struct spdlog::source_loc,enum spdlog::level::level_enum,class fmt::v8::basic_string_view<wchar_t>,wchar_t const (&)[13])" (??$log_@AAY0N@$$CB_W@logger@spdlog@@IAEXUsource_loc@1@W4level_enum@level@1@V?$basic_string_view@_W@v8@fmt@@AAY0N@$$CB_W@Z)
4>main.obj : error LNK2019: unresolved external symbol "void __cdecl spdlog::details::os::utf8_to_wstrbuf(class fmt::v8::basic_string_view<char>,class fmt::v8::basic_memory_buffer<wchar_t,250,class std::allocator<wchar_t> > &)" (?utf8_to_wstrbuf@os@details@spdlog@@YAXV?$basic_string_view@D@v8@fmt@@AAV?$basic_memory_buffer@_W$0PK@V?$allocator@_W@std@@@56@@Z) referenced in function "protected: virtual void __thiscall spdlog::sinks::win_eventlog::win_eventlog_sink<class std::mutex>::sink_it_(struct spdlog::details::log_msg const &)" (?sink_it_@?$win_eventlog_sink@Vmutex@std@@@win_eventlog@sinks@spdlog@@MAEXABUlog_msg@details@4@@Z)
4>C:\Users\user\source\repos\CMakeProject1\build\Debug\CMakeProject1.exe : fatal error LNK1120: 2 unresolved externals
4>Done building project "CMakeProject1.vcxproj" -- FAILED.
========== Rebuild All: 3 succeeded, 1 failed, 0 skipped ==========

看起来 Visual Studio 2017 没有链接到库。有人知道怎么解决吗？

【问题讨论】：

不熟悉该库，但我假设此错误消息是 spdlog 库未在 Windows 上使用正确的选项编译，从而阻止编译您可以通过定义激活使用的可选功能预处理器符号SPDLOG_WCHAR_TO_UTF8_SUPPORT

【参考方案1】：

扩展@f*** 的评论，你应该

set(SPDLOG_WCHAR_TO_UTF8_SUPPORT ON)

在add_subdirectory 调用have CMake set that preprocessor symbol for you 之前。