Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Thu, 10 Jul 2014 23:00:48 -0000

On 07/10/2014 05:14 PM, mdavidsaver wrote:
>> In dbUnitTest.c shouldn't the Type arguments to OP use the
>>     epics{Int,UInt,Float}<n> names? If not I suspect there
>>     should at least be a couple more 'unsigned' keywords in
>>     there.
> 
> Before I can answer this question I think you will need to
> educate me a bit about argument type promotion in vararg
> functions.  Does va_arg() have knowledge of this?  Will
> va_arg(X,short) actually return an 'int'?

No, you just educated me, I withdraw the above comment. It would be nice
to have a source-file comment nearby saying something like "See the C
integer type promotion rules" for human readers, and maybe use that
language in the header file as well.

> Just to throw out another idea.  I have considered using
> printf style syntax just to get a compile time check.  eg.
> testdbPutField("pvname", DBF_LONG, "%d", 0) where exactly
> "%d" must be used for DBF_LONG.  As a side effect this
> would work well for DBF_STRING.

True, but it might cause problems on Windows when we add 64-bit integer
fields ("%ld" vs "%lld"). I'm about to publish a branch for comments
that introduces DBF_INT64 and DBF_UINT64 types to the database.
Unfortunately it will probably break device support for waveform and
other record types that can choose field types, because I inserted the
64-bit type IDs between ULONG and FLOAT.

- Andrew
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System