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