@Section
   @Title { Errors }
   @Tag { figerrors }
@Begin
@PP
Lout normally produces an output file that will print without mishap on
any PostScript device.  However, some of the options of {@Code "@Fig"}'s
symbols are passed through Lout to the output file without checking,
including anything containing @Code "@Fig" lengths, angles, points, and
labels.  Any errors in these options will not be detected until the file
is printed.
@PP
The most likely errors are {@I syntax @I errors}, as in
@Code "shape { 0 0 [ 0 xsize }" for example, in which a @Code "]" is
missing; @I { type errors }, as in @Code "0 0 @Distance 45" where the
right parameter is not a point; and @I { undefined errors }, arising
from labels misspelt or used before being defined.  Less commonly, the
options may all be correct but the figure is too large in some way:  too
many labels, too deeply nested, etc.
@PP
When an error is detected, @Code "@Fig" arranges for the offending page to
be printed up to the point where the error occurred, with a message nearby
describing the error.  Printing of the document is then aborted.  It is
often quite easy to find the problem, because it lies in whatever should
have been printed next.
@End @Section
