我正在尝试使用Boost的program_options库来为库构建一个简单的命令行应用程序，但它失败了一个非常奇怪的错误。这是所有有问题的代码（是的，这很简单）：
#include <iostream>
#include <stdexcept>
#include <string>
#include <boost/program_options.hpp>
#include "NCDocEngineInterop.h"
#include "NCDocumentEngine.h"
#include "NCConfigurationManager.h"
#include "NCAcquisitions.h"
namespace po = boost::program_options;
using std::cout;
using std::cerr;
using std::endl;
using std::domain_error;
using std::wstring;
void fail_if_empty(const po::variables_map& variables, const char* field) {
if (!(variables.count(field))) {
cerr << field << " is required, you must provide a value for it" << endl;
throw domain_error(field);
}
}
int main(int ac, char* av[])
{
const char* nsdk_path_option = "nsdk-path"; // NC_CONFIGURATION::NC_NSDK_PATH
const char* ocr_path_option = "ocr-path"; // NC_CONFIGURATION::NC_OCR_PATH
const char* parser_path_option = "parser-path-option"; // NC_CONFIGURATION::NC_PARSER_PATH
const char* pdf_path = "pdf-path"; // NC_CONFIGURATION::NC_PDF_PATH
const char* output_directory = "output-directory";
const char* input_file = "input-file";
po::options_description description("Runs the NDSK engine at the provided files");
description.add_options()
("help", "produce help message")
(nsdk_path_option, po::value<wstring>(), "path to the NSDK")
(ocr_path_option, po::value<wstring>(), "path to the OCR")
(parser_path_option, po::value<wstring>(), "path to the parser")
(pdf_path, po::value<wstring>(),"path to the PDF processor")
(output_directory, po::value<wstring>(), "path to the folder where the output will be stored")
(input_file, po::value<wstring>(), "path to the input file")
;
po::variables_map vm;
po::store(po::parse_command_line(ac, av, description), vm);
po::notify(vm);
fail_if_empty(vm, nsdk_path_option);
fail_if_empty(vm, ocr_path_option);
fail_if_empty(vm, parser_path_option);
fail_if_empty(vm, pdf_path);
fail_if_empty(vm, output_directory);
fail_if_empty(vm, input_file);
NCConfigurationManager::ncSetConfiguration(
NC_NSDK_PATH,
vm[nsdk_path_option].as<wstring>() );
NCConfigurationManager::ncSetConfiguration(
NC_OCR_PATH,
vm[ocr_path_option].as<wstring>() );
NCConfigurationManager::ncSetConfiguration(
NC_PARSER_PATH,
vm[parser_path_option].as<wstring>() );
NCConfigurationManager::ncSetConfiguration(
NC_PDF_PATH,
vm[pdf_path].as<wstring>() );
return 0;
}
发生的编译错误是：
错误错误C2679：二进制'＆lt;＆lt;' ：找不到哪个运营商需要 'const src'类型的右手操作数（或者没有可接受的 转换）c：\ work \ dev \ source \ src \ framework \ thirdparty \ boost \ boost \ lexical_cast.hpp 1281 1 DocumentProcessor
错误错误C2228：'.fail'左边必须有class / struct / union c：\ work \ digitalbp \ projects \ releasedev \ nsdk_4_0 \ dev \ source \ src \ framework \ thirdparty \ boost \ boost \ lexical_cast.hpp 1281 1 DocumentProcessor
您可以看到lexical_cast.hpp file here。
我不知道这里会发生什么，或者为什么这个错误发生在这个代码上。我正在使用boost 1.50.0而我现在无法升级它。我也使用Visual Studio 2010来构建它。
这是输出窗口的输出：
1>c:\work\src\framework\thirdparty\boost\boost\lexical_cast.hpp(1281): error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'const src' (or there is no acceptable conversion)
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(679): could be 'std::basic_ostream<_Elem,_Traits> &std::operator <<<wchar_t,std::char_traits<wchar_t>>(std::basic_ostream<_Elem,_Traits> &,const char *)' [found using argument-dependent lookup]
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(726): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<<wchar_t,std::char_traits<wchar_t>>(std::basic_ostream<_Elem,_Traits> &,char)' [found using argument-dependent lookup]
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(968): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<<wchar_t,std::char_traits<wchar_t>,const InputStreamable>(std::basic_ostream<_Elem,_Traits> &&,_Ty)' [found using argument-dependent lookup]
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>,
1> InputStreamable=src,
1> _Ty=src
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(1085): or 'std::basic_ostream<_Elem,_Traits> &std::operator <<<wchar_t,std::char_traits<wchar_t>>(std::basic_ostream<_Elem,_Traits> &,const std::error_code &)' [found using argument-dependent lookup]
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(186): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ostream<_Elem,_Traits> &(__cdecl *)(std::basic_ostream<_Elem,_Traits> &))'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(192): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ios<_Elem,_Traits> &(__cdecl *)(std::basic_ios<_Elem,_Traits> &))'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(199): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::ios_base &(__cdecl *)(std::ios_base &))'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(206): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::_Bool)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(226): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(short)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(260): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned short)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(280): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(int)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(305): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned int)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(325): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(345): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned long)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(366): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(__int64)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(386): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned __int64)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(407): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(float)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(427): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(double)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(447): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long double)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(467): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(const void *)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> c:\program files (x86)\microsoft visual studio 10.0\vc\include\ostream(487): or 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_streambuf<_Elem,_Traits> *)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>
1> ]
1> while trying to match the argument list '(std::basic_ostringstream<_Elem,_Traits,_Alloc>, const src)'
1> with
1> [
1> _Elem=wchar_t,
1> _Traits=std::char_traits<wchar_t>,
1> _Alloc=std::allocator<wchar_t>
1> ]
1> c:\work\src\framework\thirdparty\boost\boost\lexical_cast.hpp(1499) : see reference to function template instantiation 'bool boost::detail::lexical_stream_limited_src<CharT,Traits,RequiresStringbuffer>::shl_input_streamable<const InStreamable>(InputStreamable &)' being compiled
1> with
1> [
1> CharT=char_type,
1> Traits=traits,
1> RequiresStringbuffer=true,
1> InStreamable=src,
1> InputStreamable=src
1> ]
1> c:\work\src\framework\thirdparty\boost\boost\lexical_cast.hpp(1974) : see reference to function template instantiation 'bool boost::detail::lexical_stream_limited_src<CharT,Traits,RequiresStringbuffer>::operator <<<Source>(const InStreamable &)' being compiled
1> with
1> [
1> CharT=char_type,
1> Traits=traits,
1> RequiresStringbuffer=true,
1> Source=src,
1> InStreamable=src
1> ]
1> c:\work\src\framework\thirdparty\boost\boost\lexical_cast.hpp(1921) : while compiling class template member function 'std::wstring boost::detail::lexical_cast_do_cast<Target,Source>::lexical_cast_impl(const Source &)'
1> with
1> [
1> Target=std::wstring,
1> Source=src
1> ]
1> c:\work\src\framework\thirdparty\boost\boost\lexical_cast.hpp(2133) : see reference to class template instantiation 'boost::detail::lexical_cast_do_cast<Target,Source>' being compiled
1> with
1> [
1> Target=std::wstring,
1> Source=src
1> ]
1> c:\work\src\framework\thirdparty\boost\boost\program_options\detail\value_semantic.hpp(89) : see reference to function template instantiation 'Target boost::lexical_cast<T,std::basic_string<_Elem,_Traits,_Ax>>(const Source &)' being compiled
1> with
1> [
1> Target=std::wstring,
1> T=std::wstring,
1> _Elem=char,
1> _Traits=std::char_traits<char>,
1> _Ax=std::allocator<char>,
1> Source=std::basic_string<char,std::char_traits<char>,std::allocator<char>>
1> ]
1> c:\work\src\framework\thirdparty\boost\boost\program_options\detail\value_semantic.hpp(170) : see reference to function template instantiation 'void boost::program_options::validate<T,char>(boost::any &,const std::vector<_Ty> &,T *,long)' being compiled
1> with
1> [
1> T=std::wstring,
1> _Ty=std::string
1> ]
1> c:\work\src\framework\thirdparty\boost\boost\program_options\detail\value_semantic.hpp(163) : while compiling class template member function 'void boost::program_options::typed_value<T,charT>::xparse(boost::any &,const std::vector<_Ty> &) const'
1> with
1> [
1> T=std::wstring,
1> charT=char,
1> _Ty=std::string
1> ]
1> c:\work\src\samples\cpp\documentprocessor\documentprocessor\main.cpp(37) : see reference to class template instantiation 'boost::program_options::typed_value<T,charT>' being compiled
1> with
1> [
1> T=std::wstring,
1> charT=char
1> ]
1>c:\work\src\framework\thirdparty\boost\boost\lexical_cast.hpp(1281): error C2228: left of '.fail' must have class/struct/union
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========
答案 0 :(得分：1)
问题实际上在这里：
po::store(po::parse_command_line(ac, av, description), vm);
parse_command_line实例化basic_command_line_parser<charT>，其中charT当然是char，而不是wchar_t，因为av的类型为char**。这意味着options_description中的所有字符串都必须为basic_string<char>，即std::string而不是std::wstring。
如果您考虑它，这实际上是有意义的，因为命令行选项总是以普通的旧“c”字符串形式出现。即使它们是mbcs编码的，您也有责任使用正确的语言环境执行转换。遗憾的是，这是必要的，因为MBCS的解释是特定于语言环境的。
我看看是否可以创建一个wchar_t版本的options_description（如果您想在wmain()中使用它，但事实并非如此。options_description包含硬编码std::string s