How to replace YACC global variables !

[Mondal, Debashis E \(GE Energy\)]

Hi,
I have a yacc ( test.y ) file along with some c files to generate a executable. 
Now other c files uses yacc generated global variables ( yyv, yys, yyerrflag, 
yytmp, yystate, yyps, yypv etc ). The problem comes when I compile yacc file by 
bison ( bison -d test.y ) and try to generate executable by compiling other c 
files along with the bison generated c file, the c compiler says that undefined 
symbol : yyv, yys, yyerrflag, yytmp, yystate, yyps, yyv etc. How do I resolve 
this problem? Can anyone help me?

Thanks in advance

Debashis