gtk:builder-add-from-file (builder path)

builder -- a gtk:builder object
path -- a pathname or namestring with the name of the file to parse

Parses a file containing a gtk:builder UI definition and merges it with the current contents of the builder. This function is useful if you need to call the gtk:builder-current-object function to add user data to callbacks before loading the gtk:builder UI definition. Otherwise, you probably want the gtk:builder-new-from-file function instead.

If there is an error opening the file or parsing the description then the program will be aborted.