Subject: Re: [Boost-users] [iostreams] Is it possible for a sink to get notified when the stream is closed?
From: Václav Haisman (v.haisman_at_[hidden])
Date: 2009-03-27 16:20:33
Bob van Manen wrote, On 27.3.2009 18:43:
> Hi All,
>
> I am trying out the Boost iostreams library to build a sink, text sent
> to this sink is split up in to lines of text and each line is then being
> send over to our logging server (the function I'm calling to do this is
> static).
>
> So far I've built the write method as mentioned in the documentation for
> my sink, and push all the characters I receive in a buffer inside my
> sink class. Then I look for the end of line characters and figure out
> the lines of text. The problem I'm having is when there is no end of
> line character and the stream gets closed.
>
> Is there a way to get notified when the stream gets closed? Is there a
> better way to do this?
>
> Here is the code I have:
>
> class logging_sink
> {
> public:
> typedef char char_type;
> typedef boost::iostreams::sink_tag category;
Make this
struct category
: boost::iostreams::sink_tag
, boost::iostreams::closable_tag
{};
>
> std::streamsize write(const char* s, std::streamsize n)
> {
> buffer_.append(s, n);
> // loop over buffer and find end of lines, send them to
> logging service
> }
>
> void close()
> {
> // close is never called
> if (!buffer_.empty())
> log_message(buffer_);
> }
>
> private:
> std::string buffer_;
>
> };
>
> class logging_stream : public boost::iostreams::stream<logging_sink>
> {
> public:
> logging_stream()
> : boost::iostreams::stream<logging_sink>(logging_sink())
> {}
> };
>
> logging_stream s;
> s << "Hello World";
> s.close();
-- VH