我之前成功地使用过fmt
库,所以我不确定为什么会出现这个问题。首先,我将展示产生错误的代码:
void Logger::AttachSink(const std::string & id, LogSink sink) {
using namespace std::literals;
auto id_found = sinks.find(id) != std::endl(sinks);
if(!id_found) {
sinks.insert(std::make_pair(id, sink));
Info(
fmt::format(
"Sink \"{}\" Attached"s,
id
) // This is the line where the error is apparently happening, and I'm assuming the `id` is the culprit for some reason.
);
}
}
以下是构建日志(注意:我使用VSCode作为编辑器,并使用CMake使用Visual Studio 2019编译器构建项目):
[main] Building folder: [WORKSPACE]
[build] Starting build
[proc] Executing command: "C:\Program Files\CMake\bin\cmake.exe" --build [WORKSPACE]/build --config Debug --target ALL_BUILD -- /maxcpucount:6
[build] Microsoft (R) Build Engine version 16.7.0+b89cb5fde for .NET Framework
[build] Copyright (C) Microsoft Corporation. All rights reserved.
[build]
[build] logging.cpp
[build] [WORKSPACE]\build\vcpkg_installed\x64-windows\include\fmt\core.h(1073,9): error C2338: Cannot format argument. To make type T formattable provide a formatter<T> specialization: https://fmt.dev/latest/api.html#formatting-user-defined-types [[WORKSPACE]\build\drakeng\drakeng.vcxproj]
[build] [WORKSPACE]\build\vcpkg_installed\x64-windows\include\fmt\core.h(1070): message : while compiling class template member function 'int fmt::v7::detail::arg_mapper<Context>::map(...)' [[WORKSPACE]\build\drakeng\drakeng.vcxproj]
[build] with
[build] [
[build] Context=fmt::v7::basic_format_context<std::back_insert_iterator<fmt::v7::detail::buffer<char>>,char>
[build] ]
[build] [WORKSPACE]\build\vcpkg_installed\x64-windows\include\fmt\core.h(1259): message : see reference to function template instantiation 'int fmt::v7::detail::arg_mapper<Context>::map(...)' being compiled [[WORKSPACE]\build\drakeng\drakeng.vcxproj]
[build] with
[build] [
[build] Context=fmt::v7::basic_format_context<std::back_insert_iterator<fmt::v7::detail::buffer<char>>,char>
[build] ]
[build] [WORKSPACE]\build\vcpkg_installed\x64-windows\include\fmt\core.h(1084): message : see reference to class template instantiation 'fmt::v7::detail::arg_mapper<Context>' being compiled [[WORKSPACE]\build\drakeng\drakeng.vcxproj]
[build] with
[build] [
[build] Context=fmt::v7::basic_format_context<std::back_insert_iterator<fmt::v7::detail::buffer<char>>,char>
[build] ]
[build] [WORKSPACE]\build\vcpkg_installed\x64-windows\include\fmt\core.h(1241): message : see reference to alias template instantiation 'fmt::v7::detail::mapped_type_constant<const std::basic_string<char,std::char_traits<char>,std::allocator<char>>,Context>' being compiled [[WORKSPACE]\build\drakeng\drakeng.vcxproj]
[build] with
[build] [
[build] Context=fmt::v7::basic_format_context<std::back_insert_iterator<fmt::v7::detail::buffer<char>>,char>
[build] ]
[build] [WORKSPACE]\build\vcpkg_installed\x64-windows\include\fmt\core.h(1400): message : see reference to function template instantiation 'unsigned __int64 fmt::v7::detail::encode_types<Context,const std::basic_string<char,std::char_traits<char>,std::allocator<char>>,>(void)' being compiled [[WORKSPACE]\build\drakeng\drakeng.vcxproj]
[build] with
[build] [
[build] Context=fmt::v7::basic_format_context<std::back_insert_iterator<fmt::v7::detail::buffer<char>>,char>
[build] ]
[build] [WORKSPACE]\build\vcpkg_installed\x64-windows\include\fmt\core.h(1834): message : see reference to class template instantiation 'fmt::v7::format_arg_store<fmt::v7::basic_format_context<std::back_insert_iterator<fmt::v7::detail::buffer<char>>,char>,const std::basic_string<char,std::char_traits<char>,std::allocator<char>>>' being compiled [[WORKSPACE]\build\drakeng\drakeng.vcxproj]
[build] [WORKSPACE]\drakeng\logging.cpp(24): message : see reference to function template instantiation 'std::basic_string<char,std::char_traits<char>,std::allocator<char>> fmt::v7::format<std::string,const std::string&,char>(const S &,const std::string &)' being compiled [[WORKSPACE]\build\drakeng\drakeng.vcxproj]
[build] with
[build] [
[build] S=std::string
[build] ]
[build] Build finished with exit code 1
错误信息让人觉得
fmt
没有fmt::formatter<std::string>
的专门化(specialization),这听起来不太对,所以我可能配置错误,或者没有包含头文件等等。老实说,我很困惑。一旦有了答案,可能只是我的运气问题导致了一些愚蠢的错误。无论如何,提供的任何帮助,先行致谢。
fmt
库做过这件事,这就是为什么我感到困惑的原因。 - Drako0812