CODEWITHSUNDEEP
c++stringvectorboost-asio
nathan lachenmyer
nathan lachenmyer

Reputation: 5550

asio::buffer type for sending both std::vector and std::string

I'd like to find a single asio::buffer type / constructor that I can use to send both std::string and std::vector objects via asynch_send_to.

Please note that I'm using standalone asio, without boost!

Right now the function I'm using to send data is:

 void UdpSocket::send_datagram(asio::const_buffer buffer) {
    mSocket.async_send_to(buffer, mEndpoint,
        [this, datagram](const asio::error_code& error, std::size_t bytes_transferred) {
        if (!error) {
            // stuff...
        }
        else{ 
            // other stuff..
        }
    });
  }

I'd like to be able to use either:

  std::vector mVector;
  send_datagram(asio::buffer(mVector.data(), mVector.size());

or

  std::string mString = "hello world";
  send_datagram(asio::buffer(mString.data(), mString.length());

The above gives me a sequence of errors in buffer_sequence_adapter.hpp:

I'm a bit overwhelmed by the sheer number of buffers and the compatibility between them; can someone help me sort out what is the right type of buffer / constructor to use that can take both std::vector and std::string types?

thanks!

Upvotes: 1

Views: 1376

Answers (1)

Galimov Albert
Galimov Albert

Reputation: 7357

You can accept buffer pointer & length as a parameter, this probably is the most extendable way:

 void UdpSocket::send_datagram(const char *buf, size_t len) {
    mSocket.async_send_to(asio::buffer(buf, len), mEndpoint,
        [this, datagram](const asio::error_code& error, std::size_t bytes_transferred) {

This enables you to use nearly any storage for this, for convenience you can write simple overload(s) like this:

void send_datagram(const std::string &s) { send_datagram(s.c_str(), s.size()); }
void send_datagram(const std::vector<char> &s) { send_datagram(s.data(), s.size()); }

But in this snippets you should keep in mind some things:

  1. You should keep source buffer alive until async operation completes.
  2. Do not copy data/buffers (do not allow data to be free()'d/deleted on scope exit as in your 1st snippet)

Upvotes: 1

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