Re: libpq: PQcmdStatus, PQcmdTuples signatures can be painlessly improved - Mailing list pgsql-hackers

On tis, 2011-12-13 at 07:55 -0500, Alex Goncharov wrote:
>   char *PQcmdStatus(PGresult *res);
>   char *PQcmdTuples(PGresult *res);
> 
> Unreasonable:
> 
>   a. What, these two can modify 'res' I pass in?..
> 
>   b. Oh, yes, because they return 'char *' pointing to
>      'res->cmdStatus+n', so, a libpq user may write:
> 
>         char *s = PQcmdStatus(res);
>         *s = 'x';
> 
>      and have 'res' modified.  (Would be the user's fault, of course.)
> 
Note that const PGresult * would only warn against changing the fields
of the PGresult struct.  It doesn't do anything about changing the data
pointed to by pointers in the PGresult struct.  So what you are saying
doesn't follow.