C++ :: Saving Packets Of Data To A Vector?

I am receiving packets of data from an ethernet cable. This is the line of code that is streaming in data from the ethernet cable:

size_t num_rx_samps = rx_stream->recv(&buff.front(), buff.size(), md, 3.0, enable_size_map);[code]

Here are the segments of me trying to push the packets onto a vector:

[code]
std::vector<size_t> processing_queue; //HERE IS WHERE I'M TRYING TO PUSH THE PACKETS ONTO A VECTOR
processing_queue.push_back(num_rx_samps);
[code]

I previously had my program saving to a .dat file (the commented out lines), but I need to change it to pushing values onto a vector so I can stream the data packets from the ethernet cable to be processed. However, the packets aren't being pushed onto the stack as I suspected. What do I need to change to push the data packets onto a vector? The following is the code:

[code]

#include <uhd/types/tune_request.hpp>
#include <uhd/utils/thread_priority.hpp>
#include <uhd/utils/safe_main.hpp>
#include <uhd/usrp/multi_usrp.hpp>
#include <uhd/exception.hpp>
#include <boost/program_options.hpp>

[code]....