dns - PHP Warning: unpack(): Type n: not enough input - log entry -

so have found error log

php warning:  unpack(): type n: not enough input, need 2, have 0 in {{file}}{{line}} 

the said file , line contains code:

$answerheader    = unpack('ntype/nclass/nttl/nlength', $answerheaderbin); 

this part of code makes query on dns. issue don;t know how debug this. if try dump before mentioned header information correct. tried unpack() no arguments , returns false no errors.

so guess, question is: in situation warning appear in error log?

turns out warning appears when input data not correct, if expects more characters unpack provided amount, in case unpack() function evaluates false.