cxxopts

• 简介
  • cxxopts是一个轻量级的C++命令行解析库，它提供了易于使用的API来定义和解析命令行选项。它支持多种类型的选项，并且允许用户自定义选项的处理逻辑。
• 项目地址： cxxopts GitHub

快速入门

轻量级C++选项解析库，支持标准的GNU样式语法。

1. cmake环境配置

include(FetchContent)
FetchContent_Declare(cxxoptsGIT_REPOSITORY https://github.com/jarro2783/cxxoptsGIT_TAG v3.2.1GIT_SHALLOW TRUE)
FetchContent_MakeAvailable(cxxopts)
# 给项目代码链接cxxopts库
target_link_libraries(cxx_opt_guide PRIVATE cxxopts::cxxopts)

2. 定义解析的规则

具体规则请看代码注释，总体来说还是比较通俗易懂的，不需要特别多的解释。

// 1. 导入头文件（只有一个）
#include <cxxopts.hpp>// 2. 创建一个Options实例
cxxopts::Options options("MyProgram", "One line description of MyProgram");// 3. 写入可解析的参数
options.add_options()("d,debug", "Enable debugging") // 默认是bool类型("i,integer", "Int param", cxxopts::value<int>()) // 该参数是int类型("f,file", "File name", cxxopts::value<std::string>())// vector 传递参数有 2 种方式// --value_list=1,2,3,4 一次性传递，确保没有空格// -v 1 -v 3 分多次传递，组成一个list("v,value_list", "File name", cxxopts::value<std::vector<double>>());("v,verbose", "Verbose output", cxxopts::value<bool>()->default_value("false")); // 该参数默认是false// 4. 解析参数
auto result = options.parse(argc, argv);// 5. 检查参数 d 在命令行出现了几次
int t = result.count("d")// 6. 获得参数d的值
auto v = result["d"].as<type>()// 7.(可选) 准许有未知的参数，会忽略该部分值。
// 默认是不接受未知的参数的，会直接报错。
options.allow_unrecognised_options();

3. 使用例子

我这里用Argv类模拟命令行传参，进行测试，该类取自cxxopts的官方源代码中。
可以看到我在void test_(cxxopts::Options &options) 方法中，对该功能做了测试。

#include <assert.h>
#include <cxxopts.hpp>
#include <iostream>
#include <string>using namespace std;class Argv {
public:Argv(std::initializer_list<const char *> args): m_argv(new const char *[args.size()]),m_argc(static_cast<int>(args.size())) {int i = 0;auto iter = args.begin();while (iter != args.end()) {auto len = strlen(*iter) + 1;auto ptr = std::unique_ptr<char[]>(new char[len]);strcpy(ptr.get(), *iter);m_args.push_back(std::move(ptr));m_argv.get()[i] = m_args.back().get();++iter;++i;}}const char **argv() const { return m_argv.get(); }int argc() const { return m_argc; }private:std::vector<std::unique_ptr<char[]>> m_args{};std::unique_ptr<const char *[]> m_argv;int m_argc;
};void test_(cxxopts::Options &options) {options.add_options()("long", "a long option")("s,short", "a short option")("quick,brown", "An option with multiple long names and no short name")("f,ox,jumped", "An option with multiple long names and a short name")("over,z,lazy,dog", "An option with multiple long names and a short name, not listed first")("value", "an option with a value", cxxopts::value<std::string>())("a,av", "a short option with a value", cxxopts::value<std::string>())("6,six", "a short number option")("p, space", "an option with space between short and long")("period.delimited", "an option with a period in the long name")("nothing", "won't exist", cxxopts::value<std::string>());Argv argv({"tester","--long","-s","--value","value","-a","b","-6","-p","--space","--quick","--ox","-f","--brown","-z","--over","--dog","--lazy","--period.delimited",});auto **actual_argv = argv.argv();auto argc = argv.argc();auto result = options.parse(argc, actual_argv);assert(result.count("long") == 1);assert(result.count("s") == 1);assert(result.count("value") == 1);assert(result.count("a") == 1);assert(result["value"].as<std::string>() == "value");assert(result["a"].as<std::string>() == "b");assert(result.count("6") == 1);assert(result.count("p") == 2);assert(result.count("space") == 2);assert(result.count("quick") == 2);assert(result.count("f") == 2);assert(result.count("z") == 4);assert(result.count("period.delimited") == 1);auto& arguments = result.arguments();assert(arguments.size() == 16);assert(arguments[0].key() == "long");assert(arguments[0].value() == "true");assert(arguments[0].as<bool>() == true);assert(arguments[1].key() == "short");assert(arguments[2].key() == "value");assert(arguments[3].key() == "av");
}int main(int argc, char **argv) {cxxopts::Options options("命令解析的标题", "这里写一下介绍");test_(options); //具体实现请看该函数return 0;// 添加一组解析参数options.add_options()("b,bar", "Param bar", cxxopts::value<std::string>())("d,debug", "Enable debugging",cxxopts::value<bool>()->default_value("false"))("f,foo", "Param foo",cxxopts::value<int>()->default_value("10"))("h,help", "Print usage");// 参加第二组解析参数options.add_options()("c,cds", "cds test",cxxopts::value<std::string>()->default_value("cds test parameter"));// 是否准许未知参数// options.allow_unrecognised_options();// 解析参数auto result = options.parse(argc, argv);// 参数是否出现if (result.count("help")) {std::cout << options.help() << std::endl;exit(0);}// 获取参数值bool debug = result["debug"].as<bool>();std::string bar;if (result.count("bar")) {bar = result["bar"].as<std::string>();cout << "bar: " << bar << endl;}int foo = result["foo"].as<int>();cout << "foo: " << foo << endl;cout << result["c"].as<std::string>();return 0;
}