Re: ASYN command string with null character

[Marty Kraimer <mrk@aps.anl.gov>]

Bruins, Stefan wrote:

> I presume this change has to be made in the "devSupportGpib.c" file of the
> asyn driver in the function "writeIt"? Will a make of the ASYN module be
> sufficient or must I run the makeSupport command a second time (this may be
> a stupid question but I'm pretty new to EPICS/ASYN etc...)
>  


No devSupportGpib.c does not need to be changed.

What you need to do is implement GPIBCVTIO. The devGpib documentation 
states:

GPIBCVTIO

   Supports record types:

   ai, ao, bi, bo, event, longin.longout, mbbi, mbbo, mbbiDirect,
   mmboDirect, stringin, stringout, waveform.

   All I/O is done by the |convert| routine, which must be defined.
   |convert| is called by a callback routine and thus can make an
   arbitrary number of calls to low level drivers. It is passed the
   address of |gpibDpvt| which contains the information needed to call
   the low level drivers: |asynCommon, asynOctet, and asynGpib.| Note
   that | asynGpib| may not be present, i.e. |pasynGpib| is null.
   |gpibDpvt| also contains a field |pupvt| which can be used by the
   convert routine. Is is initialized to null. The macro |gpibCmdGet|
   can be used to get the address of |gpibCmd| which contains other
   usefull information.

Your convert routine can start something like:

static int myConvert(struct gpibDpvt *pgpibDpvt, int P1, int P2, char **P3)
{
 asynUser *pasynUser = pgpibDpvt->pasynUser;
 gpibCmd *pgpibCmd = gpibCmdGet(pgpibDpvt);
 asynOctet *pasynOctet = pgpibDpvt->pasynOctet;
 void *asynOctetPvt = pgpibDpvt->asynOctetPvt;
 asynStatus status;


Look in devSupportGpib.h for the definitions of gpibCmd, which contains 
the info in the gpibCmd in your source code.

I think Eric Norum has an example of how to implement GPIBCVTIO.

Marty Kraimer