Re: [GENERAL] Executing regex in C code

Gabriel Furstenheim Milerud <furstenheim@gmail.com> writes:
> I'm trying to execute the equivalent to '~' with regexp from within C code.

>   text * s = cstring_to_text("aa");
>   text * p = cstring_to_text("a");
>   return DatumGetBool(DirectFunctionCall2(textregexeq, PointerGetDatum(s),
> PointerGetDatum(p)));

> But I'm getting an error with collate:
> ERROR:  could not determine which collation to use for regular expression
> HINT:  Use the COLLATE clause to set the collation explicitly.

Yes, you need to use DirectFunctionCall2Coll() if you're trying to invoke
a collation-aware function.  It's probably good enough to pass
DEFAULT_COLLATION_OID, although if you're inside a SQL function of
your own, passing down whatever collation was passed to you would
be a better plan.

                        regards, tom lane