How to identify incompatible use of pack and unpack. And how to fix it for following examples if they are incompatible uses. I want to use code around it in perl 5.22. This is present in perl 5.8 currently and working fine. I dont know if it will break or work when I upgrade perl to v5.22 

pack("$L", unpack("$L", $_)
sprintf("%08x", unpack("N",function($relay))); 
push(@rv, join('.', unpack("CCCC", function($i)))); 
unpack("u", $len . $1 ); 
unpack("w*", $v); 
unpack("V", $v) == 1
unpack("x$start_offset x4 $L$L$L$L$S$S$L$L", $file); 
unpack("x$d_off $S/a", $file); 
unpack("H*", shift); 

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In reply to pack unpack incompatibility issue by powerperl
in thread Incompatibility after perl 5.10 packing and UTF-8 strings by powerperl

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