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examples/linux/cantime.cpp 3.33 KB
48b4c725   Peter M. Groen   Setting up Socket-pp
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  // cantime.cpp
  //
  // Linux SoxketCAN writer example.
  //
  // This writes the 1-sec, 32-bit, Linux time_t value to the CAN bus each
  // time it ticks. This is a simple (though not overly precise) way to
  // synchronize the time for nodes on the bus
  //
  // --------------------------------------------------------------------------
  // This file is part of the "sockpp" C++ socket library.
  //
  // Copyright (c) 2021 Frank Pagliughi
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  // 1. Redistributions of source code must retain the above copyright notice,
  // this list of conditions and the following disclaimer.
  //
  // 2. Redistributions in binary form must reproduce the above copyright
  // notice, this list of conditions and the following disclaimer in the
  // documentation and/or other materials provided with the distribution.
  //
  // 3. Neither the name of the copyright holder nor the names of its
  // contributors may be used to endorse or promote products derived from this
  // software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  // IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  // THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  // --------------------------------------------------------------------------
  
  #include <iostream>
  #include <string>
  #include <chrono>
  #include <thread>
  #include "sockpp/can_socket.h"
  #include "sockpp/can_frame.h"
  #include "sockpp/version.h"
  
  #include <net/if.h>
  #include <sys/ioctl.h>
  
  using namespace std;
  
  // The clock to use to get time and pace the app.
  using sysclock = chrono::system_clock;
  
  // --------------------------------------------------------------------------
  
  int main(int argc, char* argv[])
  {
  	cout << "Sample SocketCAN writer for 'sockpp' "
  		<< sockpp::SOCKPP_VERSION << endl;
  
  	string canIface = (argc > 1) ? argv[1] : "can0";
  	canid_t canID = (argc > 2) ? atoi(argv[2]) : 0x20;
  
  	sockpp::socket_initializer sockInit;
  
  	sockpp::can_address addr(canIface);
  	sockpp::can_socket sock(addr);
  
  	if (!sock) {
  		cerr << "Error binding to the CAN interface " << canIface << "\n\t"
  			<< sock.last_error_str() << endl;
  		return 1;
  	}
  
  	cout << "Created CAN socket on " << sock.address() << endl;
  	time_t t = sysclock::to_time_t(sysclock::now());
  
  	while (true) {
  		// Sleep until the clock ticks to the next second
  		this_thread::sleep_until(sysclock::from_time_t(t+1));
  
  		// Re-read the time in case we fell behind
  		t = sysclock::to_time_t(sysclock::now());
  
  		// Write the time to the CAN bus as a 32-bit int
  		auto nt = uint32_t(t);
  
  		sockpp::can_frame frame { canID, &nt, sizeof(nt) };
  		sock.send(frame);
  	}
  
  	return (!sock) ? 1 : 0;
  }