DTYP + Link order

[Luedeke Andreas <Andreas.Luedeke@psi.ch>]

Hi all,
we observed a strange "mis-feature" with our database files. Actually
it seems that the configuration of a VME_IO hardware link depends on the
order of DTYP and INP/OUT definition in the .db file. Is this meant to
be that way? If not, what have we done wrong?

I have the following .db file:

record(ao,"test:I-SET") {

  field(DTYP,"Psc_IP")

  field(OUT,"#C1 S2 @set_ref_current")

}

with the definition in .dbd:

device(ao,VME_IO,devAoPscLink,"Psc_IP")

driver(drvPscIp)

The init routine of the driver is:

STATIC long init_record_ai(struct aiRecord *p_rec)

{

    struct vmeio* vmeio=&(p_rec->out.value.vmeio);

    printf( "init_record_ao: (#C%i S%i @%s)\n", vmeio->card, vmeio->signal, vmeio->parm );

    spc_lincnv_ao(p_rec, TRUE);

    return ( init_record_generic(p_rec, &p_rec->dpvt, p_rec->out.value.vmeio, p_rec->out.type, PSC_LINK_WORD_WRITE_REG, 0) );

}

In that case, I get the correct output from iocInit:
init_record_ao: (#C1 S2 @set_ref_current)

if I only exchange the field definition lines in my .db file to:

record(ao,"test:I-SET") {

  field(OUT,"#C1 S2 @set_ref_current")

  field(DTYP,"Psc_IP")

}

then I get the output:
init_record_ao: (#C0 S0 @)

After looking in the source of dbLoadRecord.c, I think it is meant to be that way. In the function yyparse, each line is interpreted after another. If the field OUT is parsed, the current setting of pdbentry->pflddes->field_type is used to determine the parsing procedure. I don't know what's the default setting of the field type, but it seems to be not VME_IO.

I neither found anything written down in the application developers guide nor in the record reference manual and searching for some keywords in tech-talk didn't gave useful results. I can't believe that I'm the first one stumbling over that. Maybe the one who has written the stuff can comment on it.

Thanks
    Andreas

-- 
Andreas Luedeke, Controls Group, Swiss-Light-Source, PSI
mailto:luedeke@psi.ch, tel:+41-(0)56-310-4002, fax:-3351