b64decode errors...

I think it's been this way for a while. I have rules going back about two years where I was using catch to handle b64decode errors. The general method I've tried is to use catch and check that the result is not null length:

 
  Try to base64 decode $string_b64encoded. Handle errors using catch. 
    Successful execution of b64decode by catch will return 0 and the output will be written to $string_b64decoded 
 if {[catch {b64decode $string_b64encoded} string_b64decoded] == 0 and $string_b64decoded ne ""}{ 
     base64 decoding succeeded 
 } else { 
     base64 decoding failed 
 } 
 

Aaron