Quick Start (C)¶

Project Setup¶

This example project setup uses CMake to build your project. In order to use system dependencies you must first install linq-network and it’s dependencies into your system. For example on how to compile and install linq-network and it’s dependencies, see Library Configuration Options

CMakeLists.txt with system depenencies¶

CMakeLists.txt

add_executable(server main.c)
target_link_libraries(server linq-netw)
install(TARGETS server DESTINATION ${CMAKE_INSTALL_PREFIX}/bin)

Build application

mkdir build
cd build
cmake -DLINQ_USE_SYSTEM_DEPENDENCIES:BOOL=ON ..
make
make install

CMakeLists.txt for reproducible builds¶

Download dependencies

git submodule add https://bitbucket.org/Altronix/linq-network external/linq-network
git submodule add https://github.com/zeromq/libzmq external/libzmq
git submodule add https://github.com/zeromq/czmq external/czmq

CMakeLists.txt

add_subdirectory(external/linq-network)
add_subdirectory(external/libzmq)
add_subdirectory(external/czmq)
add_executable(server main.c)
target_link_libraries(server linq-netw)
install(TARGETS server DESTINATION ${CMAKE_INSTALL_PREFIX}/bin)

Build application

mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=./install ..
make
make install

Create LinQ Network Callbacks (Optional)¶

To initialize the LinQ Network library you may optionally pass in function pointers to callbacks that will be called during LinQ Network Events.

Alert Callback¶

The “Alert Callback” is called from the LinQ Network library when a LinQ Enabled device generates an alert. An optional application context, alert struct, and a email struct are passed into your application alert callback function.

static void
on_alert(
    void* ctx,
    linq_network_alert_s* alert,
    linq_network_email_s* mail,
    device_s** d)
{
  // ...
}

See Also

Heartbeat Callback¶

The “Heartbeat Callback” is called from the LinQ Network library when a LinQ Enabled device sends a heartbeat. An optional application context, and the device serial number are passed into your application heartbeat callback function.

static void
on_heartbeat(void* ctx, const char* serial, device_s** d)
{
   // ...
}

See Also

linq_network_callbacks

Error Callback¶

The “Error Callback” is called from the LinQ Network library when the LinQ Network library detects a runtime error. An optional application context, and an linq_network_error are passed into your application error callback function.

static void
on_error(void* ctx, E_LINQ_ERROR e, const char* what, const char* serial)
{
  // ...
}

See Also

CTRLC Callback¶

The “Ctrlc Callback” is called from the LinQ Network library when the LinQ Network library is about to shutdown. An optional application context is passed into your application ctrlc callback function.

static void
on_ctrlc(void* ctx)
{
  // ...
}

See Also

linq_network_callbacks

Process Network IO¶

The LinQ Network library performs non-blocking IO inside of your thread. To process LinQ Network IO you must call the linq_network_poll routine from inside of your main loop. linq_network_poll() will call any callbacks you have provided from the same thread context as your main application.

int
main(int argc, char* argv[])
{
   // Initialize your app
   // ...

   while(sys_running())
   {
     linq_network_poll(linq, 5);
   }

   // ...
}

Note

For multi threaded support, use one of the higher level language bindings that provide thread safe wrappers, or create your own IPC scheme per your applications needs.

See Also

linq_network_poll
sys_running

Complete Application¶

// Include the Altronix Header
#include "altronix/linq_network.h"

// Declare your application callbacks
static void on_error(void* ctx, E_LINQ_ERROR e, const char *sid, device_s**d);
static void on_alert(void* ctx, linq_network_alert_s* alert, linq_network_email_s* mail);
static void on_heartbeat(void* ctx, const char *serial, device_s** d);
linq_network_callbacks callbacks = {.err = on_error, .alert = on_alert, .hb = on_heartbeat};

int
main(int argc, char *argv[])
{
  int err = -1;
  linq_network_socket s;

  // Create a linq-network context
  linq_network_s *network = linq_network_create(&callbacks, NULL);
  if(!server) return err;

  // Listen for incoming device connections...
  s = linq_network_listen(server, "tcp://*:33455");

  // Process Socket IO every 5ms
  while (sys_running())
  {
    linq_network_poll(server, 5);
  }

  // Free linq-network context
  linq_network_destroy(&server);
}

static void
on_error(void* ctx, E_LINQ_ERROR e, const char *sid, device_s**d)
{
  //  ...
}

static void
on_alert(void* ctx, linq_network_alert_s* alert, linq_network_email_s* mail)
{
  // ...
}

static void
on_heartbeat(void* ctx, const char *serial, device_s** d)
{
  // ...
}