Porting from AT&T yacc to bison

[Mike Bezman]

Hi !!
I am trying to port lex/yacc code which was compiled by AT&T lex/yacc before
to be compiled by Flex/Bison.
The code compiles ok ,but
when I am trying to run my example using Flex/Bison version of the compiled
code it doesn't seem to recognize anything (i.e. tokens and grammas) from
Yacc file. It worked fine before (with AT&T versions).
Anything I am mising ?
My options:  flex -l and bison -t -d

Thanks, Mike