GtkEntry::set_width_chars
void set_width_chars(int
n_chars);
Changes the size request of the entry to be about the right size for
n_chars characters. Note that it changes the
size request, the size can still be affected by how you pack the
widget into containers. If n_chars is
-1, the size reverts to the default entry size.
参照:
get_width_chars()