GTK Hello World complains about undefined references - c

Question

I'm using Linux Mint 20 to learn GTK. I installed the following package to get started:
sudo apt-get install build-essential libgtk-3-dev
And then proceeded to compile the Hello World app in 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_window_close), window);
gtk_container_add (GTK_CONTAINER (button_box), button);
gtk_widget_show_all (window);
}
int
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;
}
As the example requests, I compiled it using:
gcc `pkg-config --cflags gtk+-3.0` -o hello-world-gtk hello-world-gtk.c `pkg-config --libs gtk+-3.0`
But it didn't work, and I have no idea why. It's output was:
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libwayland-client.so.0: referência não definida para "ffi_type_void#LIBFFI_BASE_7.0"
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libwayland-client.so.0: referência não definida para "ffi_call#LIBFFI_BASE_7.0"
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libwayland-client.so.0: referência não definida para "ffi_type_uint32#LIBFFI_BASE_7.0"
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libwayland-client.so.0: referência não definida para "ffi_type_sint32#LIBFFI_BASE_7.0"
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libwayland-client.so.0: referência não definida para "ffi_prep_cif#LIBFFI_BASE_7.0"
/usr/bin/ld: /usr/lib/x86_64-linux-gnu/libwayland-client.so.0: referência não definida para "ffi_type_pointer#LIBFFI_BASE_7.0"
collect2: error: ld returned 1 exit status
The "referência não definida para" is Portuguese to something like "undefined reference for".
Anyone knows what I need to do?

Answer 1

I've managed it! The thing is, for some reason my system missed libffi. I downloaded it's latest version, and just installed it:
./configure
(...)
make
(...)
sudo make install
(...)
I've compiled it, and it worked!