Re: [HACKERS] How do I construct a varlena?

> My problem is in how to get the compiler to treat the malloced space as
> a varlena.
> 
> I have this (abridged) C code, to be used with 
> CREATE FUNCTION cname(bpchar, bpchar, bpchar) returns bpchar ...:
> 
> 
>   char *cxname;
> 
>   text cname (text s, text t, text f)
>   {
>         text *result;
>   ...
>         cxname = realloc((void *) cxname, strlen(tmp)+sizeof(struct varlena));
>         strcpy(cxname+sizeof(int32), tmp);
> ->      result = &((struct varlena) cxname);
>         result->vl_len = strlen(tmp);
> 
>         return *result;
>   }
> 
> but the compiler gives the error `conversion to non-scalar type requested'
> at the marked line.

I gues something like this should work:

    struct varlena *cxname

    cxname = (struct varlena *)
		realloc(cxname, strlen(tmp) + VARHDRSZ);
    strcpy(cxname->vl_dat, tmp); /* maybe '&cxname->vl_dat' */
    return cxname;

I don't think it's possible to 'return *cxname', cos the compiler will
only return the part of your data.

Most of this is from head, so check on things if they don't work immediately.

Maarten

_____________________________________________________________________________
| TU Delft, The Netherlands, Faculty of Information Technology and Systems  |
|                   Department of Electrical Engineering                    |
|           Computer Architecture and Digital Technique section             |
|                          M.Boekhold@et.tudelft.nl                         |
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