libdevel-callsite-perl - 1.0.1-1+b3 main

Devel::Callsite module provides subroutines to get the caller return OP
address and perl interpreter context.
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The callsite() function returns the OP address of the caller, a number,
one level up from where it was called. It's useful for functions that
need to uniquely know where they were called, such as Every::every();
see Every. Or it can be used to pinpoint a location with finer
granularity than a line number (see
http://www.perlmonks.com/?node_id=987268). In conjunction with an OP
tree disassembly you can know exactly where the caller is located in
the Perl source.
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The context() function returns the interpreter context as a number.
This is a fairly unique number together with the call site.