Experimental Physics and
Industrial Control System

"Priller, John" <[email protected]> · Wed, 1 Jul 2015 12:32:15 +0000

I have code that uses epicsScanDouble to convert a string-representation
of floating point numbers to actual floating-point, and I've found
there's a behavior change from R3.14.12.2 to R3.15 (either .1 or .2)

I wrote a simple little test program to demonstrate it, the output for
R3.14.12.2 looks like this:

    EPICS 3.14.12.2 epicsScanDouble test
    status: 1  value:       3.1415  for input string: ' 3.1415 '
    status: 1  value:    6.022e+23  for input string: ' 6.022e+23 '
    status: 0  value:            0  for input string: ' bob '
    status: 1  value:         5.43  for input string: ' 5.43V '
    status: 1  value:         6.78  for input string: ' 6.78 A '

But under R3.15.2 I get:

    EPICS 3.15.2 epicsScanDouble test
    status: 1  value:       3.1415  for input string: ' 3.1415 '
    status: 1  value:    6.022e+23  for input string: ' 6.022e+23 '
    status: 0  value:            0  for input string: ' bob '
    status: 0  value:            0  for input string: ' 5.43V '
    status: 0  value:            0  for input string: ' 6.78 A '

Skimming the source it appears that epicsScanDouble is now a macro
calling epicsParseDouble with a units pointer of NULL.  If I call
epicsParseDouble directly with units=NULL this does indeed fail, but if
I pass it a valid pointer it then succeeds.

So, question: was this an intentional change, that units/etc off the end
of the number string now cause epicsScanDouble to fail?   I can
#if/#else the code to call epicsParseDouble if it's available, and I
guess I'll have to do that for now, but that's the sort of version
dependency I'd like to avoid if at all possible.

Any feedback appreciated, even if it's "no, you're doing it all wrong..."

-- 
John A. Priller             | Phone : (517) 908-7375
MSU Cyclotron Laboratory    | Email : [email protected]
640 S. Shaw Lane room 4220Z | Web   : http://people.nscl.msu.edu/~priller/
East Lansing, MI 48824      |

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System