Enabeling location tracking for bison 1.75

[Oliver B. Fischer]

Dear list,

I would like to provide a better error message to the users of my 
application. To achieve this I would like to enable location tracking in 
my bison parser. Sadly, I am not able to convince it.

I redefined YYLLOC_DEFAULT

#define YYLLOC_DEFAULT(Current, Rhs, N)          \
  Current.first_line   = Rhs[1].first_line;      \
  Current.first_column = Rhs[1].first_column;    \
  Current.last_line    = Rhs[N].last_line;       \
  Current.last_column  = Rhs[N].last_column;     \
  fprintf(stderr, "loc(%d) [l%d,c%d l%d,c%d] [l%d,c%d l%d,c%d]\n", N, \
    Rhs[1].first_line, Rhs[1].first_column, \
    Rhs[1].last_line, Rhs[1].last_column, \
    Rhs[N].first_line, Rhs[N].first_column, \
    Rhs[N].last_line, Rhs[N].last_column);

and put

%locations

in my grammar file.

If I parse an input file, my scanner never gives me the true position of 
any symbol. I get ony 0s.

Can someone help me?

Regards,

Oliver Fischer