Create a simple hello-world application

1 Overview[edit]

This stage explains how to create, build and execute a simple C code application using the freshly installed SDK.

2 Code[edit]

  • Create a directory that will host your source codes
For ecosystem release  v2.1.0 More info.png :
PC $> mkdir $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.1.0/Developer-Package/stm32mp1-openstlinux-20-11-12
PC $> mkdir $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.1.0/Developer-Package/stm32mp1-openstlinux-20-11-12/sources
For ecosystem release  v2.0.0 More info.png :
PC $> mkdir $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.0.0/Developer-Package/stm32mp1-openstlinux-20-06-24
PC $> mkdir $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.0.0/Developer-Package/stm32mp1-openstlinux-20-06-24/sources
  • Create a directory for your user space example
For ecosystem release  v2.1.0 More info.png :
PC $> mkdir $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.1.0/Developer-Package/stm32mp1-openstlinux-20-11-12/sources/gtk_hello_world_example
PC $> cd $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.1.0/Developer-Package/stm32mp1-openstlinux-20-11-12/sources/gtk_hello_world_example
For ecosystem release  v2.0.0 More info.png :
PC $> mkdir $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.0.0/Developer-Package/stm32mp1-openstlinux-20-06-24/sources/gtk_hello_world_example
PC $> cd $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.0.0/Developer-Package/stm32mp1-openstlinux-20-06-24/sources/gtk_hello_world_example

  • Create the source code file for your user space example: gtk_hello_world.c
#include <gtk/gtk.h>

static void
print_hello (GtkWidget *widget,
             gpointer   data)
  g_print ("Hello World\n");

static void
activate (GtkApplication *app,
          gpointer        user_data)
  GtkWidget *window;
  GtkWidget *button;
  GtkWidget *button_box;

  window = gtk_application_window_new (app);
  gtk_window_set_title (GTK_WINDOW (window), "Window");
  gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);

  button_box = gtk_button_box_new (GTK_ORIENTATION_HORIZONTAL);
  gtk_container_add (GTK_CONTAINER (window), button_box);

  button = gtk_button_new_with_label ("Hello World");
  g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);
  g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_widget_destroy), window);
  gtk_container_add (GTK_CONTAINER (button_box), button);

  gtk_widget_show_all (window);

main (int    argc,
      char **argv)
  GtkApplication *app;
  int status;

  app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
  g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
  status = g_application_run (G_APPLICATION (app), argc, argv);
  g_object_unref (app);

  return status;

3 Build[edit]

  • Create the makefile for your user space example: Makefile
Info white.png Information
All the indentations in a makefile are tabulations
PROG = gtk_hello_world
SRCS = gtk_hello_world.c


# Add / change option in CFLAGS and LDFLAGS
CFLAGS += -Wall $(shell pkg-config --cflags gtk+-3.0)
LDFLAGS += $(shell pkg-config --libs gtk+-3.0)

all: $(PROG)

$(PROG): $(SRCS)
	$(CC) -o $@ $^ $(CFLAGS) $(LDFLAGS)

	rm -f $(CLEANFILES) $(patsubst %.c,%.o, $(SRCS))
  • Cross-compile the project
PC $> make

4 Deploy and execute[edit]

  • Push this binary into the board (Ethernet connection needed)
PC $> scp gtk_hello_world root@<board ip address>:/usr/local
  • Execute your user space example
Board $> cd /usr/local/
Board $> ./gtk_hello_world
(gtk_hello_world:6370): dbind-WARNING **: 18:17:49.914: Error retrieving accessibility bus address: org.a11y.Bus.Error: Failed to execute chi)
  • A GTK windows is displayed
GTK Hello world window
  • Click on the "Hello world" button to close the window. Hello world is displayed in the console:
Hello world