我正在使用 socket.io-clientpp，https://github.com/ebshimizu/socket.io-clientpp，它使用 rapidjson。
当收到一个事件时，我的函数被调用：
void data_published(socketio::socketio_events&, const Value& v) {
值是一个 rapidjson 值。我的问题是我看到将其字符串化的唯一方法是使用 Document 类。但是要将值放入文档中，所有函数都采用非常量引用，例如：
GenericValue& AddMember(const Ch* name, GenericValue& value, Allocator& allocator) {
我习惯了 jsonpp，我想我错过了一些愚蠢的东西。问题很简单：如何对 const rapidjson 值进行字符串化？
I am the author of rapidjson. Thank you for your question. I recorded this to issue in http://code.google.com/p/rapidjson/issues/detail?id=45
It is due to that GenericValue::Accept() is non-const.
As GenericValue::Accept() just generates events for handler, it does not need to modify the value and its decedents. So it should change from:
template <typename Handler>
GenericValue& Accept(Handler& handler)
to
template <typename Handler>
const GenericValue& Accept(Handler& handler) const
You may patch this to your rapidjson/document.h or download the latest version (trunk or 0.1x branch).
After this change, you can stringfy a const Value as in tutorial:
const Value& v = ...;
FileStream f(stdout);
PrettyWriter<FileStream> writer(f);
v.Accept(writer);
Or to a string buffer:
const Value& v = ...;
StringBuffer buffer;
PrettyWriter<StringBuffer> writer(buffer);
v.Accept(writer);
const char* json = buffer.GetString();