Re: Need to use streams/buffers, but NOT related to cout, cin or to files

From:
"Alf P. Steinbach" <alfps@start.no>
Newsgroups:
comp.lang.c++
Date:
Sat, 12 Sep 2009 20:02:35 +0200
Message-ID:
<h8gnnu$l5u$1@news.eternal-september.org>
* Ramon F Herrera:

I have looked all over the net for this, but all the hits I get are
about cout, cin or streams linked to disk files.

The feature that I need is in-core (boy, that's an ancient term)
streams and buffers.

Back when I was a C programmer, I implemented my own streaming like
this:

char output_buffer[150 *1024];
char pointer = *output_buffer;

pointer += sprintf(pointer, "Some text here %s\n", somevariable1);
pointer += sprintf(pointer, "Some more text here %s\n",
somevariable2);
pointer += sprintf(pointer, "Some further stuff here %s\n",
somevariable3);

I then discovered something that looks exactly what I need, but it is
inside the Boost library. See snippet below.

I bet that standard C++ and/or the STL must contain some facility that
performs the functionality of the code below.

TIA,

-Ramon

--------------------------

    boost::asio::streambuf request;
    std::ostream request_stream(&request);
    request_stream << "GET " << argv[2] << " HTTP/1.0\r\n";
    request_stream << "Host: " << argv[1] << "\r\n";
    request_stream << "Accept: */*\r\n";
    request_stream << "Connection: close\r\n\r\n";

    // Send the request.
    boost::asio::write(socket, request);


You're already using Boost.

Boost has some support for "in-core" streams, that is, memory mapped streams,
for interprocess communication.

But possibly what you want is something far simpler, namely like

     #include <sstream>
     #include <string>

     ...
     std::ostringstream stream;
     stream << "Some text here " << someVariable1 << "\n";
     stream << "Some more text here " << someVariable2 << "\n";
     stream << "Some further stuff here " << someVariable3 << "\n";

     std::string const s = stream.str();

where std::ostringstream is one of the std::stringstream "bethren"[?] that Peter
Koch Larsen referred you to.

Cheers & hth.,

- Alf

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