C++系统相关操作2 - 获取系统环境变量

1. 关键词

C++ 系统调用 环境变量 getenv 跨平台

2. sysutil.h

#pragma once
#include <cstdint>
#include <string>
namespace cutl
{
/**
* @brief Get an environment variable.
*
* @param name the name of the environment variable.
* @param default_value the default value if the variable is not found.
* @return std::string the value of the environment variable.
*/
std::string getenv(const std::string &name, const std::string &default_value);
} // namespace cutl

3. sysutil.cpp

#include <map>
#include <iostream>
#include <strutil.h>
#include <cstdlib>
#include "sysutil.h"
#include "inner/logger.h"
#include "inner/system_util.h"
#include "inner/filesystem.h"
namespace cutl
{
std::string getenv(const std::string &name, const std::string &default_value)
{
const char *text = std::getenv(name.c_str());
if (text == nullptr)
{
CUTL_ERROR("variable [" + name + "] not set, fallback to " + default_value);
return default_value;
}
return std::string(text);
}
} // namespace cutl

4. 测试代码

#include "common.hpp"
#include "sysutil.h"
void TestGetEnv()
{
PrintSubTitle("TestGetEnv");
auto result = cutl::getenv("PATH", "not found");
std::cout << "getenv for PATH, result:" << std::endl
<< result << std::endl;
// for Windows testing
std::cout << "USERPROFILE: " << cutl::getenv("USERPROFILE", "not found") << std::endl;
std::cout << "PROCESSOR_ARCHITECTURE: " << cutl::getenv("PROCESSOR_ARCHITECTURE", "not found") << std::endl;
// FOR UNIX/LINUX/MAC testing
std::cout << "HOME: " << cutl::getenv("HOME", "not found") << std::endl;
}

5. 运行结果

---------------------------------------------TestGetEnv---------------------------------------------
getenv for PATH, result:
/usr/local/bin:/usr/local/sbin:/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/usr/local/go/bin
USERPROFILE: [2024-06-21 21:32:28.863][E]]0x7ff85b8d5fc0](cutl) [sysutil.cpp:208:getenv] variable [USERPROFILE] not set, fallback to not found
not found
PROCESSOR_ARCHITECTURE: [2024-06-21 21:32:28.863][E]]0x7ff85b8d5fc0](cutl) [sysutil.cpp:208:getenv] variable [PROCESSOR_ARCHITECTURE] not set, fallback to not found
not found
HOME: /Users/spencer

6. 源码地址

更多详细代码,请查看本人写的C++ 通用工具库: common_util, 本项目已开源,代码简洁,且有详细的文档和Demo。

posted @   陌尘(MoChen)  阅读(76)  评论(0编辑  收藏  举报
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