Bitwise operator for error reporting

[terryds]

Can someone explain me about bitwise operators for error reporting ?

 

I've slightly understood about bitwise operators for numbers (http://www.litfuel.net/tutorials/bitwise.htm)

 

But, What i don't understand is how to use it for error reporting? What will the symbol ^ , ~ , &, | mean ?

[davej]

$a & $b And 	Bits that are set in both $a and $b are set.$a | $b Or 	Bits that are set in either $a or $b are set.$a ^ $b Xor 	Bits that are set in $a or $b but not both are set.~ $a 	Not 	Bits that are set in $a are not set, and vice versa.$a << $b Shift left 	Shift the bits of $a $b steps to the left (each step means "multiply by two")$a >> $b Shift right 	Shift the bits of $a $b steps to the right (each step means "divide by two") 

In other words;

 

$mask = 1;// this is actually something like 000000001 only bit zero is a one

$mask2 = ~$mask; // this flips the bits so it is now something like 1111111111110

$out1 = $in | $mask; // now bit zero is forced to be a one

$out2 = $in & $mask2; // now bit zero is forced to be a zero

Edited October 20, 2013 by davej

[birbal]

error reporting constant is also a number. so applying bitwise operator on them is same as applying on numbers.