Experimental Physics and
Industrial Control System

Hi Eric,

 

I have a new proposal that I think can make us both happy.  Andrew agrees that this is the best solution.

 

-          Keep the existing stringout behavior, numchars passed to driver does not include trailing nil

-          Modify waveform output behavior so that if val[nord-1]==0 then it passes numchars=nord-1 else it passes numchars=nord.  This is the device support called asynOctetWrite.  Update the documentation to say that this device support is intended for use only with strings.

-          Add a new device support called asynOctetWriteBinary.  It always passes numchars=nord.

 

This makes the behavior of stringout and waveform records the same for asynOctetWrite.

 

It has 2 potential backwards compatibility issues.  These will be clearly flagged in the release notes.

 

-          Drivers that are expecting to receive numchars that includes the trailing nil for strings from waveform records.  I would be surprised if this is a problem, because such drivers would currently be getting a different behavior with stringout records.

-          Applications that are using devAsynOctet to send binary data to drivers.  Such applications will need their databases changed to use the new asynOctetWriteBinary device support.

 

Mark