The GPL "Special Exception" and yacc.c

[David Wootelhoff]

Hi,

I'm considering using a Bison generated parser in a closed source
commercial product.

I see that the C file output by Bison has a section starting "As a
special exception" which refers to "the Bison parser skeleton". Does
this paragraph mean I can modify yacc.c itself (which I understand is
the skeleton) and still keep my generated parser closed source? My
initial interpretation was that this was indeed the case, but I see
that yacc.c itself only contains the standard GPL notice and no
"Special Exception". (I'm aware that the special exception definitely
applies to the bison generated C file).

I'd like to use Bison with a modified skeleton but I don't want to
violate the GPL. Any clarification is much appreciated.

Regards

David