Could you shared how the program knows the record length ?

I'm not sure I understand this question. You have defined the 'record length' to be two bytes (16 bits) in little-endian (or 'VAX') order in the second and third positions in your example string. The 'v' unpack template specifier unpacks just such a value. (The 'x' skips over the first character/byte position.)

In reply to Re^3: How to sort record using pack function ? by AnomalousMonk
in thread How to sort record using pack function ? by bh_perl

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