环境路径目录迭代 [英] Environment PATH Directories Iteration

问题描述

我不能找到任何代码（不是C和C ++ Boost.Filsystem）关于如何迭代（解析） PATH中存在的目录环境变量优先以独立于平台的方式。这不是很难写，但如果可用，我想重用标准模块。链接或建议任何人？

I cant find any code (neither C nor C++ Boost.Filsystem) on how to iterate (parse) the directories present in the PATH environment variable in preferrably in a platform-independent way. It is not so hard to write but I want to reuse standard modules if they are available. Links or suggestions anyone?

推荐答案

这是我以前使用过的：

const vector<string>& get_environment_PATH()
{
    static vector<string> result;
    if( !result.empty() )
        return result;

#if _WIN32
    const std::string PATH = convert_to_utf8( _wgetenv(L"PATH") ); // Handle Unicode, just remove if you don't want/need this. convert_to_utf8 uses WideCharToMultiByte in the Win32 API
    const char delimiter = ';';
#else
    const std::string PATH = getenv( "PATH" );
    const char delimiter = ':';
#endif
    if( PATH.empty() )
        throw runtime_error( "PATH should not be empty" );

    size_t previous = 0;
    size_t index = PATH.find( delimiter );
    while( index != string::npos )
    {
        result.push_back( PATH.substr(previous, index-previous));
        previous=index+1;
        index = PATH.find( delimiter, previous );
    }
    result.push_back( PATH.substr(previous) );

    return result;
}

这只会在程序运行时计算一次。它也不是线程安全的，但是，没有任何环境相关的。

This only "calculates" the thing once per program run. It's not really thread-safe either, but heck, nothing environment-related is.

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