Why a function starts with @ in php ? like @unpack(xxx)?

Question

$block_header = @unpack('Sc_size/Su_size/Lchecksum', fread($this->fp, 8));

What does this mean ?

Answer 1

PHP Error Control Operators.

it avoids showing the error returned by the function. more info in the link:

http://www.php.net/manual/en/language.operators.errorcontrol.php