Thanks kennethk,
What i knew was 'use' puts the modules in compile-time,
so i assumed how ever circular the 'use' call may be, at the point of execution, both the A.pm and B.pm are well resolved.
Can you plese let me know how perl walks through the above script(abc.pl), and may fail in loading some functions.
Wanted to have a clear picture of how perl compiles and executes.