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小的电商网站,网站制作与防护费用,wordpress国内工作室主题,西安公司网站建设一、模块开发 在前面的开发中#xff0c;基本都是使用标准库中的模块直接调用。在本文中#xff0c;将自己开发一个模块供程序调用#xff0c;这样#xff0c;就可以真正的进入了模块自行开发的实际应用场景。这和前面的动态库开发的思想有些类似#xff0c;大家可以对比着…一、模块开发在前面的开发中基本都是使用标准库中的模块直接调用。在本文中将自己开发一个模块供程序调用这样就可以真正的进入了模块自行开发的实际应用场景。这和前面的动态库开发的思想有些类似大家可以对比着来看。二、编写一个模块并调用看一下自定义模块的代码//exportdemo.hexport module demo;import std;namespace demo{exportintAdd(int,int);export class exportDemo{public:exportDemo();public:voiddisplay();};}//exportdemo.cppmodule demo;import std;namespace demo{intAdd(inta,intb){returnab;}exportDemo::exportDemo(){}voidexportDemo::display(){std::coutthis is demo module!std::endl;}}标准的头文件加cpp文件再看一下调用代码import std;import demo;intmain(){demo::exportDemo d;d.display();std::coutmain app!Add return:demo::Add(1,2)std::endl;return0;}首先使用命令行进行编译1. 先编译std.o g -stdc23 -fmodules-ts -fsearch-include-path -c bits/std.cc 在当前目录下可以发现生成的std.o和gcm文件夹 2. 编译模块文件 g -stdc23 -fmodules-ts -c exportdemo.h 会报一个错误 exportdemo.h:4:8: error: module-declaration not permitted in header-unit 4 | export module demo;看错误的说明是不能将模块声明放到头文件好那就随便起一个名字比如exportdemo.cm,再次编译g -stdc23 -fmodules-ts -c exportdemo.cm会报另外一个警告和一个错误g: warning: exportdemo.cm: linker input file unused because linking not done error: exportdemo.cm: linker input file not found: 没有那个文件或目录看这样子应该是没找到相关的输入文件。再次修改文件名称为exportdemo.cppm并重新编译g -stdc23 -fmodules-ts -c exportdemo.cppm编译成功。给大家留一个问题这个模块文件名称是否可以随便取叫exportdemo.ixx或exportdemo.ccm、exportdemo.cxxm可不可以还有没有其它的规则限制再模块编译成功的基础上继续编译3. 编译所有单元 g -stdc23 -fmodules-ts -o demo exportdemo.cpp main.cpp编译成功在当前路径下有一个demo可执行文件执行它./demo this is demo module! main app!Add return:3说明编译流程整体走通没有问题。三、使用cmake编译先看一下cmakelists.txt的文件内容cmake_minimum_required(VERSION 3.31.6 ) set(CMAKE_EXPERIMENTAL_CXX_IMPORT_STD 0e5b6991-d74f-4b3d-a41c-cf096e0b2508) set(CMAKE_CXX_COMPILER clang) set(CMAKE_C_COMPILER clang) set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdliblibc) set(CMAKE_EXE_LINKER_FLAGS ${CMAKE_EXE_LINKER_FLAGS} -stdliblibc) set(CMAKE_CXX_EXTENSIONS OFF) set(CMAKE_CXX_STANDARD 23) set(CMAKE_CXX_STANDARD_REQUIRED ON) set(CMAKE_CXX_MODULE_STD 1) set(CMAKE_EXPORT_COMPILE_COMMANDS ON) project(cmakeMouduleFirst LANGUAGES CXX) add_executable(cmakeMouduleFirst) target_sources(cmakeMouduleFirst PRIVATE main.cpp exportdemo.cpp PRIVATE FILE_SET demoMmodules TYPE CXX_MODULES FILES exportdemo.cppm )文件内容整体和上一次的没有太大差别主要是增加了对新增模块的引用在target_sources增加相关的模块文件编译文件。然后使用cmake编译mkdir build cd build cmake -G Ninja .. -- The CXX compiler identification is Clang 20.1.8 -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Check for working CXX compiler: /usr/bin/clang - skipped -- Detecting CXX compile features -- Detecting CXX compile features - done -- Configuring done (1.9s) CMake Error in CMakeLists.txt: The CXX_MODULE_STD property on the target cmakeMouduleFirst requires that the __CMAKE::CXX23 target exist, but it was not provided by the toolchain. Reason: Experimental import std support not enabled when detecting toolchain; it must be set before CXX is enabled (usually a project() call) -- Generating done (0.0s) CMake Generate step failed. Build files cannot be regenerated correctly.这是原来用g编译才报得错误啊想了一下忽然想到刚刚编译了一个最新cmake 4.0,并临时在环境变量里进行了指定。会不是是这个原因呢然后查看了一下cmake版本果然是4.0,重新打开一个终端再次查看了一下cmake版本是3.31.6。重新使用上面的命令编译cmake -G Ninja .. -- The CXX compiler identification is Clang 20.1.8 -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Check for working CXX compiler: /usr/bin/clang - skipped -- Detecting CXX compile features CMake Warning (dev) at /usr/share/cmake-3.31/Modules/Compiler/CMakeCommonCompilerMacros.cmake:248 (cmake_language): CMakes support for import std; in C23 and newer is experimental. It is meant only for experimentation and feedback to CMake developers. Call Stack (most recent call first): /usr/share/cmake-3.31/Modules/CMakeDetermineCompilerSupport.cmake:113 (cmake_create_cxx_import_std) /usr/share/cmake-3.31/Modules/CMakeTestCXXCompiler.cmake:83 (CMAKE_DETERMINE_COMPILER_SUPPORT) CMakeLists.txt:19 (project) This warning is for project developers. Use -Wno-dev to suppress it. -- Detecting CXX compile features - done -- Configuring done (0.4s) -- Generating done (0.0s)编译成功。这就是那个cmake中“CMAKE_EXPERIMENTAL_CXX_IMPORT_STD”对应的ID的问题。执行编译后的可执行文件可呈现与直接编译相同的结果。四、总结对新技术的学习不用突飞猛进细雨无声慢慢掌握即可。其实对于模块编程目前尚未听说哪家公司已经在大规模的铺开所以还是有时间慢慢来学习并应用于实践的。