Merge pull request #2470 from mavlink/pr-param-example

examples: add get_all_params example

examples/CMakeLists.txt

@@ -36,6 +36,7 @@ add_subdirectory(mavshell)
 add_subdirectory(multiple_drones)
 add_subdirectory(offboard)
 add_subdirectory(parachute)
+add_subdirectory(params)
 add_subdirectory(set_actuator)
 add_subdirectory(sniffer)
 add_subdirectory(system_info)

examples/params/CMakeLists.txt

@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.10.2)
+
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+project(params)
+
+add_executable(params
+    params.cpp
+)
+
+find_package(MAVSDK REQUIRED)
+
+target_link_libraries(params
+    MAVSDK::mavsdk
+)
+
+if(NOT MSVC)
+    add_compile_options(params PRIVATE -Wall -Wextra)
+else()
+    add_compile_options(params PRIVATE -W2)
+endif()

examples/params/params.cpp

@@ -0,0 +1,86 @@
+//
+// Simple example to demonstrate how to get and set params.
+//
+
+#include <mavsdk/mavsdk.h>
+#include <mavsdk/plugins/param/param.h>
+#include <chrono>
+#include <cstdint>
+#include <iostream>
+#include <future>
+
+using namespace mavsdk;
+
+void usage(const std::string& bin_name)
+{
+    std::cerr << "Usage :" << bin_name << '\n'
+              << "Connection URL format should be :\n"
+              << " For TCP : tcp://[server_host][:server_port]\n"
+              << " For UDP : udp://[bind_host][:bind_port]\n"
+              << " For Serial : serial:///path/to/serial/dev[:baudrate]\n"
+              << "For example, to connect to the simulator use URL: udpin://0.0.0.0:14540\n";
+}
+
+int main(int argc, char** argv)
+{
+    if (argc != 2) {
+        usage(argv[0]);
+        return 1;
+    }
+
+    const std::string connection_url = argv[1];
+
+    Mavsdk mavsdk{Mavsdk::Configuration{ComponentType::GroundStation}};
+    const ConnectionResult connection_result = mavsdk.add_any_connection(connection_url);
+
+    if (connection_result != ConnectionResult::Success) {
+        std::cerr << "Connection failed: " << connection_result << '\n';
+        return 1;
+    }
+
+    std::cout << "Waiting to discover system...\n";
+    auto prom = std::promise<std::shared_ptr<System>>{};
+    auto fut = prom.get_future();
+
+    // We wait for new systems to be discovered, once we find one that has an
+    // autopilot, we decide to use it.
+    Mavsdk::NewSystemHandle handle = mavsdk.subscribe_on_new_system([&mavsdk, &prom, &handle]() {
+        auto system = mavsdk.systems().back();
+
+        if (system->has_autopilot()) {
+            std::cout << "Discovered autopilot\n";
+
+            // Unsubscribe again as we only want to find one system.
+            mavsdk.unsubscribe_on_new_system(handle);
+            prom.set_value(system);
+        }
+    });
+
+    // We usually receive heartbeats at 1Hz, therefore we should find a
+    // system after around 3 seconds max, surely.
+    if (fut.wait_for(std::chrono::seconds(3)) == std::future_status::timeout) {
+        std::cerr << "No autopilot found, exiting.\n";
+        return 1;
+    }
+
+    // Get discovered system now.
+    auto system = fut.get();
+
+    // Instantiate plugins.
+    auto param = Param{system};
+
+    // Print params once.
+    const auto get_all_result = param.get_all_params();
+
+    std::cout << "Int params: \n";
+    for (auto p : get_all_result.int_params) {
+        std::cout << p.name << ": " << p.value << '\n';
+    }
+
+    std::cout << "Float params: \n";
+    for (auto p : get_all_result.float_params) {
+        std::cout << p.name << ": " << p.value << '\n';
+    }
+
+    return 0;
+}