C++ 获取当前目录

1. 说明

1. 如果编译器支持C++17，则建议使用std::filesystem::current_path
2. 如果只在windows平台使用，可使用_getcwd
3. 如果只在linux平台使用，可使用getcwd
4. 如果代码要跨平台使用，可以使用通过编译统一的版本

2. C++17 std::filesystem::current_path

#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main()
{
    std::cout << "Current working directory: " << fs::current_path() << '\n'; 
}

Current working directory:  "D:/local/ConsoleApplication1"

std::filesystem::current_path 还可以改变当前目录
https://en.cppreference.com/w/cpp/filesystem/current_path

3. windows平台 _getcwd

#include <direct.h>

std::string current_working_directory()
{
    char buff[250];
    _getcwd(buff, 250); 
    std::string current_working_directory(buff);
    return current_working_directory;
}

int main()
{
    std::cout << "Current working directory: " << current_working_directory() << endl;
}

直接使用getcwd会有告警
https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/getcwd-wgetcwd?view=msvc-160

4. linux平台 getcwd

#include <unistd.h>

int main() 
{
    char buff[250];
    getcwd(buff, 250);
    string current_working_directory(buff);
    cout << "Current working directory: " << current_working_directory<< endl;

    return 0;
}

或者使用get_current_dir_name

#include <unistd.h>

int main() 
{
    char *cwd = get_current_dir_name();
    cout << "Current working directory: " << cwd << endl;
    free(cwd);

    return 0;
}

https://man7.org/linux/man-pages/man3/getcwd.3.html
https://linux.die.net/man/3/get_current_dir_name

5. 通过编译宏统一两者版本

参考： https://www.tutorialspoint.com/find-out-the-current-working-directory-in-c-cplusplus

#if defined(_MSC_VER)
    #include <direct.h>
    #define GetCurrentDir _getcwd
#elif defined(__unix__)
    #include <unistd.h>
    #define GetCurrentDir getcwd
#else
#endif

std::string get_current_directory() 
{
    char buff[250]; 
    GetCurrentDir(buff, 250);
    string current_working_directory(buff);
    return current_working_directory;
}

int main(int argc, char* argv[])
{
    std::cout << "Current working directory: " << get_current_directory() << endl;
    
    return 0;
}