标签：des style blog http io color ar os for
我的boost为1.56而不是1.55
boost在xml的例子给出了一段写xml文件的代码，我简化如下：
void debug_settings::save(const std::string &filename) { using boost::property_tree::ptree; ptree pt; pt.put("debug.filename", m_file); pt.put("debug.level", m_level); write_xml(filename, pt); }
这段代码写出来的格式非常难看，没有缩进的。于是在网上查找了下,需要改成下面的样子：
void debug_settings::save(const std::string &filename) { using boost::property_tree::ptree; ptree pt; pt.put("debug.filename", m_file); pt.put("debug.level", m_level); boost::property_tree::xml_writer_settings<char> settings(‘\t‘,1); write_xml(filename, pt,std::local(),settings); }
意思是缩进1个\t，结果报了一大堆错误：
In instantiation of ‘class boost::property_tree::xml_parser::xml_writer_settings<char>‘: ../../game_server/common/CServerSetting.cpp:97:61: required from here ../../game_server/libraries/boost_1_56_0/boost/property_tree/detail/xml_parser_writer_settings.hpp:38:35: error: ‘char‘ is not a class, struct, or union type typedef typename Str::value_type Ch;
本人水平在菜，没见过此类错误。去百度，也找不到类似的结果。看xml_parser_writer_settings的源代码，也看不懂。白白浪费了几个小时，终于受不了，翻出去请教google，很快找到了相关的解决方案：
http://www.pcl-users.org/PCL-compilation-errors-Please-help-me-td4035209.html
This is because there is a breaking API change in the boost 1.56.0 property_tree, as compared to boost 1.55.0. For more reference, see an issue described here: link. I fixed this by modifying: boost::property_tree::xml_writer_settings<char> settings (‘\t‘, 1); write_xml (filename, pt, std::locale (), settings); To: auto settings = boost::property_tree::xml_writer_make_settings<std::string> (‘\t‘, 1); write_xml (filename, pt, std::locale (), settings); In the 3 or so places this occurs... Thanks, McDamon
http://lists.boost.org/boost-users/2014/08/82693.php
Dear all, with the release of Boost 1.56, on Ubuntu 14.04 (g++ 4.8.2, 64 bit), code like the following suddenly fails to compile: pt::xml_writer_settings<char> settings(‘\t‘, 1); pt::write_xml(someFileName, ptr_out, std::locale(), settings); "pt" is obviously an alias for boost::property_tree. The error message I‘m getting is /opt/boost156/include/boost/property_tree/detail/xml_parser_writer_settings.hpp:38:35: error: ‘char‘ is not a class, struct, or union type typedef typename Str::value_type Ch; I can see the following possibly relevant change in property_tree: In Boost 1.55, from xml_parser.hpp: ----------------------------------- template<typename Ptree> void write_xml( const std::string & , const Ptree & , const std::locale & = std::locale() , const xml_writer_settings<typename Ptree::key_type::value_type >& = xml_writer_settings<typename Ptree::key_type::value_type >() ); In Boost 1.56, same header: --------------------------- template<typename Ptree> void write_xml( const std::string & , const Ptree & , const std::locale & = std::locale() , const xml_writer_settings<typename Ptree::key_type > & = xml_writer_settings<typename Ptree::key_type >() ); So xml_writer_settings is now given a Ptree::key_type instead of a Ptree::key_type::value_type which I assume is the reason for the above error. Is there a portable way to specify the type of indention character in write_xml ? Best Regards, Beet
由于我没有启用C++11，改为这样写
boost::property_tree::xml_writer_settings<string> settings = boost::property_tree::xml_writer_make_settings<string> (‘ ‘, 4); write_xml( DEFAULTCONFIG,pt,std::locale(),settings );
问题解决。
PS：大伙以后搜索代码用这个http://www.gfsoso.com/。百度找找电影院什么的就好，搜代码实现是不靠谱。
标签：des style blog http io color ar os for
原文地址：http://www.cnblogs.com/coding-my-life/p/4070201.html
