c++ - C++ "hello world" Boost tee 示例程序

Question

Boost C++ 库有Function Template tee

类模板 tee_filter 和 tee_device 提供了两种拆分输出序列的方法，以便将所有数据同时定向到两个不同的位置。

我正在寻找一个完整的 C++ 示例，使用 Boost tee 输出到标准输出和像“sample.txt”这样的文件。

Answer 1

根据约翰链接的问题的帮助：

#include <boost/iostreams/tee.hpp>
#include <boost/iostreams/stream.hpp>
#include <fstream>
#include <iostream>

using std::ostream;
using std::ofstream;
using std::cout;

namespace bio = boost::iostreams;
using bio::tee_device;
using bio::stream;

int main()
{
    typedef tee_device<ostream, ofstream> TeeDevice;
    typedef stream<TeeDevice> TeeStream;
    ofstream ofs("sample.txt");
    TeeDevice my_tee(cout, ofs); 
    TeeStream my_split(my_tee);
    my_split << "Hello, World!\n";
    my_split.flush();
    my_split.close();
}

Answer 2

这是一个使用tee_filter我当前用于 Boost.Test 输出的示例：

{ // init code, use static streams to keep them alive until test run process end

    using namespace boost::iostreams;
    static ofstream ofs("boost_test_output.log.xml"); // log file
    static tee_filter<ostream>  fileFilt(ofs); // tee all passed data to logfile

    // note derives from `boost::iostreams::output_filter`
    static text_xml_readability_filter xmlFilt; // filter all passed data, making the XML output readable

    static filtering_ostream filter; // master filter

    filter.push(fileFilt); // 1st, tee off any data to the file (raw boost XML)
    filter.push(xmlFilt);  // 2nd make the xml data stream readable (linebreaks, etc.)
    filter.push(cout);     // 3rd output the readable XML to cout

    boost::unit_test::unit_test_log.set_stream( filter );
}