WEBVTT 00:00.080 --> 00:04.100 In this lesson you will see how to create a Ros2 Cplusplus package. 00:04.100 --> 00:09.860 Please make sure that you watch the previous video on how to create a Python package so you can better 00:09.860 --> 00:10.550 understand. 00:10.550 --> 00:14.480 And the first thing is to navigate inside your Ros2 workspace. 00:14.480 --> 00:17.960 So for example, from anywhere you just go back to your home directory. 00:17.960 --> 00:22.700 You go to the roster workspace and inside the source folder okay. 00:22.880 --> 00:24.950 Here we already have one package. 00:24.950 --> 00:26.870 So my Python package. 00:26.870 --> 00:32.540 And that's where we will put all the packages for our application for our workspace. 00:32.540 --> 00:40.580 So now that you are in this source folder you can do Ros2 and then pkg create okay. 00:40.610 --> 00:41.990 So that's the same command. 00:42.020 --> 00:43.730 Then we're going to give a name. 00:43.730 --> 00:47.330 So let's do my CP pkg. 00:47.360 --> 00:52.850 So once again you can name it as you want as long as it makes sense here for this example. 00:52.850 --> 00:57.170 And for this first package of this course I just name it my C plus plus package. 00:57.170 --> 01:01.000 We need to provide a build type. 01:01.090 --> 01:06.820 And this time the build type is going to be element underscore CMake. 01:06.850 --> 01:10.090 That's going to create a C plus plus package. 01:10.120 --> 01:10.330 Okay. 01:10.360 --> 01:13.750 So we had element Python for Python packages. 01:13.750 --> 01:17.320 And we have element cmake for C plus plus packages. 01:17.320 --> 01:21.760 And as you will see the architecture of the package is going to be completely different. 01:21.760 --> 01:23.920 So with that command that's going to be enough. 01:23.920 --> 01:25.570 You can already launch it. 01:25.570 --> 01:29.260 But if we want we can also add dependencies okay. 01:29.260 --> 01:32.800 And I'm going to add a dependency this time to our CL cpp. 01:32.980 --> 01:38.020 So we have our clcp which is the C plus plus library for ros2. 01:38.050 --> 01:42.820 And that's going to allow you to write C plus plus code to interact directly with the functionalities 01:42.820 --> 01:43.810 of Ros2. 01:43.840 --> 01:48.430 And you can add as many dependencies you want after this option here. 01:48.430 --> 01:49.870 For now we just add one. 01:49.900 --> 01:52.270 We're going to add more later in this course. 01:52.270 --> 01:58.330 So now that I have this command inside the source folder I can press enter. 01:58.330 --> 02:00.580 And that's going to create another package. 02:00.580 --> 02:04.840 So you can see we also have some logs creating folders and files. 02:04.840 --> 02:09.460 We also have a warning for the license okay but no need to worry about that. 02:09.460 --> 02:11.110 We don't need a license for now. 02:11.110 --> 02:15.010 And so let's do a clear here LZ. 02:15.010 --> 02:18.880 And you can see we have a my C plus plus package. 02:18.880 --> 02:25.150 So let's open VSCode and well if you have closed VSCode make sure you go back again. 02:25.180 --> 02:30.610 You go back to your source folder and then you do code dot always like that. 02:30.610 --> 02:33.370 That's what I always do and I never have any problem. 02:33.370 --> 02:40.750 So you press enter here and you can see we have still our Python package. 02:40.780 --> 02:43.210 Our C plus plus package now is right here. 02:43.210 --> 02:45.790 And the architecture is quite different. 02:45.790 --> 02:51.250 As you can see here for a C plus plus package we have an include folder with the name. 02:51.340 --> 02:54.010 So another folder with the name of the package. 02:54.010 --> 02:56.860 And then we have a source folder after that. 02:56.860 --> 02:59.580 We also have a CMake list dot txt. 02:59.940 --> 03:05.370 So I'm just going to ignore all of the pop ups here because we already have the correct extensions in 03:05.370 --> 03:06.000 VSCode. 03:06.000 --> 03:13.890 And as you can see, well, if you already know a bit of C plus plus that's typically a well a C plus 03:13.890 --> 03:14.610 plus project. 03:14.610 --> 03:17.940 You have a source and include folder and then a cmakelists.txt. 03:18.000 --> 03:23.940 So this is really basically a standard C plus plus architecture inside the Ros2 package. 03:23.970 --> 03:24.270 All right. 03:24.300 --> 03:26.610 So that's going to be the implementation files. 03:26.640 --> 03:30.330 The CPP files in the include you have the header files. 03:30.360 --> 03:33.150 There's going to be the HPP files or the H files. 03:33.150 --> 03:38.550 And then in Cmakelists.txt you're going to write the rules to build your code. 03:38.580 --> 03:42.030 Okay I'm going to come back to the Cmakelists.txt when we write the first note. 03:42.030 --> 03:43.860 For now let's just close that. 03:43.860 --> 03:46.350 And you see we also have a package dot XML. 03:46.350 --> 03:49.830 And this one is very similar to the one we had for Python. 03:49.860 --> 03:50.040 Okay. 03:50.070 --> 03:51.330 So package dot XML. 03:51.360 --> 03:57.800 Basically this is the only file that you need to have in every Ros2 to package. 03:57.830 --> 03:58.070 Okay. 03:58.100 --> 04:00.110 So that's the minimum thing you need to have. 04:00.110 --> 04:05.660 And as you can see we also have name version description emails license. 04:05.660 --> 04:07.940 So we have all those things. 04:08.000 --> 04:10.760 If you want to publish the package you will need to fill those. 04:10.760 --> 04:13.580 Then you see we have the Aim and CMake here. 04:13.610 --> 04:14.540 That's the build type. 04:14.540 --> 04:18.860 And we also have the dependency with the depend tag with rcl, cpp. 04:19.040 --> 04:24.710 And so if you want to add more dependencies you will need to add more depend tag just after that one. 04:24.740 --> 04:25.250 Great. 04:25.250 --> 04:28.550 So now let's go back to the terminal and let's build this package. 04:28.550 --> 04:36.080 So once again don't run call build here just in case I'm going to run call on build okay in my source 04:36.080 --> 04:36.770 folder. 04:36.980 --> 04:39.800 So I make the mistake of running call on build here. 04:39.800 --> 04:40.970 What's going to happen. 04:40.970 --> 04:43.100 Well you see it's still building stuff. 04:43.100 --> 04:49.460 And now I have to install a build and a log folder inside my source repository. 04:49.460 --> 04:53.240 But I also have the same thing in my ros2 workspace. 04:53.240 --> 04:59.630 So if you have that well things can be confusing and you might have a lot of errors in the future. 04:59.630 --> 05:03.680 So if you have made a mistake, it's not a problem you just remove. 05:03.680 --> 05:08.420 So let's do a remove with recursive of the build, install and log. 05:08.450 --> 05:14.150 Okay, so that's just to show you that if you build in the wrong place, make sure you remove all those 05:14.150 --> 05:15.020 folders. 05:15.020 --> 05:20.450 And then make sure you build exactly in this Ros2 workspace. 05:20.840 --> 05:23.780 So now I can do call on build. 05:25.820 --> 05:30.770 And you can see we are building the C plus plus package and the Python package. 05:30.770 --> 05:39.020 And if I only want it to build the C plus plus package I can do call build with packages select and 05:39.020 --> 05:42.020 then my C plus plus package. 05:42.050 --> 05:46.760 I press enter and you can see that we only build that package okay. 05:46.790 --> 05:48.530 So this option is very useful. 05:48.560 --> 05:49.100 Great. 05:49.130 --> 05:50.720 Now you have a C plus plus package. 05:50.720 --> 05:52.310 You also have a Python package. 05:52.310 --> 05:55.880 So let's see what a node is and then let's create one.