Conversion between BpChar and "C" char

Dear all,

Can anyone give me a hint about converting and casting between
BpChar and char..  I'm trying to return the value off buff, and I have the
example from one site in zcech language. So I'm looking for the missing
link.. Because I think I do not handle the memory calls correclty     ;-(
If I get on the right rack I'm very pleased ofcource...    ;-)

    int     *idx;
    int     *varlen;
    char    *buff[40];
    char    *term = "\n";
    char    *line = "-";

    varlen = (int *) flow;

    while (idx <= varlen) {
        idx++;
        buff[*idx]          = line;
        buff[*idx +1]       = term;
    }

    BpChar *result = palloc (VARHDRSZ + 1);
    VARATT_SIZEP (result) = VARHDRSZ + 1;
    *(VARDATA (result)) = 'M';

    PG_RETURN_BPCHAR_P (result);
    //PG_RETURN_INT32(flow);


Thanks in advance, kind regards,
Willem