Alternative to deprecated gtk_alignment_new - gtk3

Question

I used the GtkAlignment widget to control the alignment and size of its child widget. But gtk_alignment_new has been deprecated since version 3.14 and should not be used in newly-written code. What functions should I use as alternatives to let the code be gtk3+ compatible?
#include <gtk/gtk.h>
int main(int argc, char *argv[]) {
GtkWidget *window;
GtkWidget *button;
GtkWidget *halign;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(window), "Tooltip");
gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
gtk_container_set_border_width(GTK_CONTAINER(window), 15);
button = gtk_button_new_with_label("Button");
gtk_widget_set_tooltip_text(button, "Button widget");
halign = gtk_alignment_new(0, 0, 0, 0);
gtk_container_add(GTK_CONTAINER(halign), button);
gtk_container_add(GTK_CONTAINER(window), halign);
gtk_widget_show_all(window);
g_signal_connect(G_OBJECT(window), "destroy",
G_CALLBACK(gtk_main_quit), NULL);
gtk_main();
return 0;
}

Answer 1

As suggested in the comment, use these two functions instead:
void gtk_widget_set_halign (GtkWidget *widget, GtkAlign align);
Sets the horizontal alignment of widget.
gtk_widget_get_valign (GtkWidget *widget); Sets the vertical alignment of widget.
The enum GtkAlign types are the following:
GTK_ALIGN_START: The 'start' of the layout. Vertically this is the top, horizontally this is left/right according to LTR/RTL
GTK_ALIGN_END: Opposite of GTK_ALIGN_START
GTK_ALIGN_CENTER: The middle of the layout
GTK_ALIGN_FILL : Take all available space
for scaling use GTK_ALIGN_FILL.
So the gtk3+ compatible alternative for your code is the following:
#include <gtk/gtk.h>
int main(int argc, char *argv[]) {
GtkWidget *window;
GtkWidget *button;
gtk_init(&argc, &argv);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_window_set_title(GTK_WINDOW(window), "Tooltip");
gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
gtk_container_set_border_width(GTK_CONTAINER(window), 15);
button = gtk_button_new_with_label("Button");
gtk_widget_set_tooltip_text(button, "Button widget");
gtk_widget_set_halign (button, GTK_ALIGN_START);
gtk_widget_set_valign (button, GTK_ALIGN_START);
gtk_container_add (GTK_CONTAINER (window), button);
g_signal_connect(G_OBJECT(window), "destroy",
G_CALLBACK(gtk_main_quit), NULL);
gtk_widget_show_all(window);
gtk_main();
return 0;
}