c++ 要包含哪些文件和库？

Question

很多时候我在互联网上找到有用的代码示例。大约一半的时间他们没有指定要包含哪些文件，甚至没有在命令行中使用 -l 指定要包含哪些库。你通常如何发现它？

编辑说明:下面的问题已经解决。可以跳过这篇文章的其余部分。

现在，我在尝试编译时遇到了很多错误:

53: string Gunzip::gunzip(string& compressed)
54: {
55:   namespace io = boost::iostreams;
56:
57:   io::filtering_istream gunzip;
58:   gunzip.push(io::gzip_decompressor());
59:   std::istringstream in_stream = std::istringstream(compressed);
60:   gunzip.push(in_stream);
61:
62:   stringstream strstream;
63:   io::copy(gunzip, strstream);
64:   return strstream.str();
65: }

在上网一天后，我正在尝试:

option: 3 -L/usr/include/boost
and:
 8: #include <string>
 9: #include <iostream>
10: #include <sstream>

15: #include <boost/iostreams/copy.hpp>
16: #include <boost/iostreams/device/array.hpp>
17: #include <boost/iostreams/device/back_inserter.hpp>
18: #include <boost/iostreams/filter/gzip.hpp>
19: #include <boost/iostreams/filter/test.hpp>
20: #include <boost/iostreams/filtering_stream.hpp>

我的错误是:

                 from /usr/include/c++/4.5/string:45,
                 from Gunzip.cpp:8:
/usr/include/c++/4.5/bits/ios_base.h: In copy constructor     ‘std::basic_ios<char>::basic_ios(const std::basic_ios<char>&)’:
In file included from /usr/include/c++/4.5/bits/localefwd.h:43:0,
/usr/include/c++/4.5/bits/ios_base.h:785:5: error: ‘std::ios_base::ios_base(const     std::ios_base&)’ is private
/usr/include/c++/4.5/iosfwd:77:11: error: within this context
/usr/include/c++/4.5/iosfwd: In copy constructor     ‘std::basic_istringstream<char>::basic_istringstream(const     std::basic_istringstream<char>&)’:
/usr/include/c++/4.5/iosfwd:97:11: note: synthesized method     ‘std::basic_ios<char>::basic_ios(const std::basic_ios<char>&)’ first required here 
/usr/include/c++/4.5/streambuf: In copy constructor     ‘std::basic_stringbuf<char>::basic_stringbuf(const std::basic_stringbuf<char>&)’:
/usr/include/c++/4.5/streambuf:773:7: error: ‘std::basic_streambuf<_CharT,     _Traits>::basic_streambuf(const std::basic_streambuf<_CharT, _Traits>::__streambuf_type&)     [with _CharT = char, _Traits = std::char_traits<char>, std::basic_streambuf<_CharT,     _Traits>::__streambuf_type = std::basic_streambuf<char>]’ is private
/usr/include/c++/4.5/iosfwd:93:11: error: within this context
/usr/include/c++/4.5/iosfwd: In copy constructor     ‘std::basic_istringstream<char>::basic_istringstream(const     std::basic_istringstream<char>&)’:
/usr/include/c++/4.5/iosfwd:97:11: note: synthesized method     ‘std::basic_stringbuf<char>::basic_stringbuf(const std::basic_stringbuf<char>&)’ first     required here 
Gunzip.cpp: In member function ‘std::string Gunzip::gunzip(std::string&)’:
Gunzip.cpp:59:65: note: synthesized method     ‘std::basic_istringstream<char>::basic_istringstream(const std::basic_istringstream<char>&)’ first required here 
make[2]: Leaving directory `/home/albert/NetBeansProjects/Arb3'
make[1]: Leaving directory `/home/albert/NetBeansProjects/Arb3'
make[2]: *** [build/Debug/GNU-Linux-x86/Gunzip.o] Error 1
make[1]: *** [.build-conf] Error 2
make: *** [.build-impl] Error 2

BUILD FAILED (exit value 2, total time: 9s)

我可以删除前 3 个包含以获得我不理解的其他错误。我不知道哪个错误更好。

1. 此错误是否与包含相关？我怎么知道？我责怪包含，因为到目前为止所有错误都是由于包含。我不知道 basic_ios 是什么。
2. 您如何找出要包含的内容以及要使用的库？

Answer 1

您发布的错误实际上不是与包含相关的错误，也不是链接器错误，而是以下行:

std::istringstream in_stream = std::istringstream(compressed);

这会导致调用标记为私有(private)的继承复制构造函数，因此您应该将其替换为:

std::istringstream in_stream(压缩);

在这种情况下，编译器输出实际上非常清晰。