Screen size of gtk_entry widget

[Richard <rruth studio disney com>]

gtk_entry_new_with_max_length controls the maximum number of characters I can
enter into a gtk_entry widget.  But HOW do I control the size
(in characters) of entry field.  The following two widgets display
the same way, and I want the second one horizontally shorter.

gtk_entry_new_with_max_length(30);

gtk_entry_new_with_max_length(2);


Thanks 
Richard