How to gzip-compress on-the-fly in C++ using boost::iostreams

This minimal example shows you how to write data to a .gz file in C++, compressing the data on-the-fly using boost::iostreams. Using the modern iostreams layer, as opposed to a block-based approach like zlib allows you to use the full power and ease-of-use of std::ostream.

#include <fstream>
#include <iostream>
#include <boost/iostreams/filtering_streambuf.hpp>
#include <boost/iostreams/copy.hpp>
#include <boost/iostreams/filter/gzip.hpp>
using namespace std;

int main(int argc, char** argv) {
    if(argc < 2) {
        cerr << "Usage: " << argv[0] << " <output .gz file>" << endl;
    //Read filename from the first command line argument
    ofstream file(argv[1], ios_base::out | ios_base::binary);
    boost::iostreams::filtering_streambuf<boost::iostreams::output> outbuf;
    //Convert streambuf to ostream
    ostream out(&outbuf);
    //Write some test data
    out << "This is a test text!\n";
    boost::iostreams::close(outbuf); // Don't forget this!
cmake_minimum_required(VERSION 3.0)
find_package(Boost 1.36.0 COMPONENTS iostreams)

add_executable(iostreams-gz-compress iostreams-gz-compress.cpp)
target_link_libraries(iostreams-gz-compress ${Boost_LIBRARIES})