You want hex($clid).

sprintf "%d" doesn't convert something that isn't a number into a number. In fact, it does the opposite. It converts numbers into their string representation.

Your test snippet is not equivalent because 0x0000000b doesn't produce the string 0x0000000b which you have in your actual code.

$ perl -wE'say sprintf "%d", "0x0000000b"'
Argument "0x0000000b" isn't numeric in sprintf at -e line 1.
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Why didn't you mention you were getting an error message?