docs: using cmake with yocto recipe - example

layers/meta-belden-coreos/recipes-core/images/coreos-image-full-cmdline.bb

@@ -3,5 +3,8 @@ functionality installed."
 
 inherit coreos-image
 
-IMAGE_FEATURES += "ssh-server podman dev-tools cockpit networkmanager swupdate"
+IMAGE_FEATURES += "ssh-server podman dev-tools cockpit networkmanager"
-IMAGE_INSTALL:append = " packagegroup-core-full-cmdline swupdate-www"
+
+IMAGE_INSTALL += "cmake-demo"
+
+IMAGE_INSTALL:append = " packagegroup-core-full-cmdline"

layers/meta-belden-coreos/recipes-demo/cmake-demo/cmake-demo_0.1.bb

@@ -0,0 +1,46 @@
+#Example how to make a recipe that uses CMake for building
+#Please note that this is a recipe to build the package. For package to be added to an Image, another recipe needs to be changed.
+#Example: This package is added to be part of coreos-image-full-cmdline image.
+#A new line: IMAGE_INSTALL += "cmake-demo" is added to layers/meta-belden-coreos/recipes-core/images/coreos-image-full-cmdline.bb
+
+DESCRIPTION = "Simple helloworld cmake application"
+
+#Recipe must include a licence
+LICENSE = "CLOSED"
+
+#Revision of this recipe (optional)
+PR = "r1"
+
+SYSTEMD_AUTO_ENABLE = "enable"
+
+#Systemd file
+SYSTEMD_SERVICE_${PN} = "hello.service"
+
+#Recipe needs to know where the needed files are
+SRC_URI += "file://CMakeLists.txt\
+		file://lib/CMakeLists.txt \
+		file://src/CMakeLists.txt \
+		file://src/helloworld.c \
+		file://src/hello.service \
+		file://lib/lib-demo.c \
+		file://lib/lib-demo.h"
+
+#List of files and directories that are placed in a package
+FILES:${PN} += "${systemd_unitdir}/system/hello.service"
+
+#Temporary work directory for each recipe where extracted source files are kept
+S="${WORKDIR}"
+
+#CMake will do most of the work, so it needs to be inherited
+inherit cmake systemd
+
+#Passing any needed configure options to CMake
+EXTRA_OECMAKE = ""
+
+#Systemd service is being installed using this function (this is an example). Other files are installed using CMake
+do_install:append() {
+  install -d ${D}/${systemd_unitdir}/system
+  install -m 0644 ${WORKDIR}/src/hello.service ${D}/${systemd_unitdir}/system
+}
+
+

layers/meta-belden-coreos/recipes-demo/cmake-demo/files/CMakeLists.txt

@@ -0,0 +1,15 @@
+#Top CMakeLists.txt file
+
+#Firstly a minimum required version of CMake is specified
+cmake_minimum_required(VERSION 3.5)
+
+#Name the project, and give a version
+project(cmake_demo VERSION 0.0.1)
+
+#Setting build logs to verbose (usefull for debugging)
+set(CMAKE_VERBOSE_MAKEFILE ON)
+
+#Adding subdirectories that contain CMakeLists.txt
+add_subdirectory(lib)
+add_subdirectory(src)
+

layers/meta-belden-coreos/recipes-demo/cmake-demo/files/lib/CMakeLists.txt

@@ -0,0 +1,17 @@
+#CMakeLists.txt file is gets some info from top CMakeLists.txt file (Minimum required version, Project name), so its not needed to redefine it here
+
+
+# Declare the library target.
+add_library(${PROJECT_NAME} SHARED lib-demo.c)
+
+# Set the version property.
+set_target_properties(${PROJECT_NAME} PROPERTIES VERSION ${PROJECT_VERSION})
+
+# Set the shared object version property to the project's major version.
+set_target_properties(${PROJECT_NAME} PROPERTIES SOVERSION ${PROJECT_VERSION_MAJOR})
+
+# Set the public header property to the one with the actual API.
+set_target_properties(${PROJECT_NAME} PROPERTIES PUBLIC_HEADER lib-demo.h)
+
+#Install library and dependency file
+install (TARGETS ${PROJECT_NAME} LIBRARY DESTINATION lib PUBLIC_HEADER DESTINATION include)

layers/meta-belden-coreos/recipes-demo/cmake-demo/files/lib/lib-demo.c

@@ -0,0 +1,12 @@
+/* 
+*  Simple C library to be used for demonstration
+*  Bitbake recipe calls CMake to buld and install
+*
+*/
+#include <stdio.h>
+#include "lib-demo.h"
+
+void demo_print(){
+	
+	printf("Print from demo lib\n");
+}

layers/meta-belden-coreos/recipes-demo/cmake-demo/files/lib/lib-demo.h

@@ -0,0 +1,4 @@
+/*
+*  Library dependency file
+*/
+void demo_print();

layers/meta-belden-coreos/recipes-demo/cmake-demo/files/src/CMakeLists.txt

@@ -0,0 +1,7 @@
+#CMakeLists.txt file is gets some info from top CMakeLists.txt file (Minimum required version, Project name), so its not needed to redefine it here
+
+#Create binary
+add_executable(helloworld helloworld.c)
+
+#Install binary
+install(TARGETS helloworld RUNTIME DESTINATION bin)

layers/meta-belden-coreos/recipes-demo/cmake-demo/files/src/hello.service

@@ -0,0 +1,10 @@
+#Systemd service file
+
+[Unit]
+Description=GNU Hello World startup script for KOAN training course
+
+[Service]
+ExecStart=/usr/bin/helloworld
+
+[Install]
+WantedBy=multi-user.target

layers/meta-belden-coreos/recipes-demo/cmake-demo/files/src/helloworld.c

@@ -0,0 +1,13 @@
+/*
+*  Simple C code (binary is used for demonstration)
+*/
+
+#include <stdio.h>
+
+int main() {
+
+   printf("Hello, World!");
+   
+   return 0;
+   
+}