Application log, BAL_LOG_MSG_ADD and basic ABAP

Assuming that many of ABABers use Application logs in own programs. And I’d clarify a few less practical than usually raise.

BAL_LOG_MSG_ADD contain a macros macro_access_data and this macros contain a line:

 

 

 

PERFORM load.
ASSIGN (‘(SAPLSBAL)G’) TO <g>.

 

 

 

And I didn’t get the logic of how the G was populated with data. Could somebody clarify it for me?

I’ve checked SAPLSBAL, and found just declaration.