The
XExtentsOfFontSet
function returns an
XFontSetExtents
structure for the fonts used by the Xmb and Xwc layers
for the given font set.
The
XFontSetExtents
structure is owned by Xlib and should not be modified
or freed by the client.
It will be freed by a call to
XFreeFontSet
with the associated
XFontSet.
Until freed, its contents will not be modified by Xlib.