Build op null handling method

[mrvsr]

Hi
I am trying to handle null in build op logic

for example

outRec.empno_setnull();

but I am getting below error while compiling.


empno_setnull is not a member of APT_Bop_output0Accessors.
1 Error(s) detected.

I have seen setting null values like this in the forum but its not working for me.
I tried to include all head files.

1. What I am missing here.
2. in APT_String class what is the function to check whether a string is null or not.
APT_String str1;

str1.isnull();

3. Please provide me the link to document that will explain using the APT_ classes and macros with example in build ops.
I have Torrent c++ orchestrate classes and macros documentation but its not a good help.