What do the double-less-than and pipe operators do?

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Reference - What does this symbol mean in PHP?

What does this line do?

$theVal = ((($theR << 8) | $theG) << 8) | $theB;

What do the << and | do?

http://php.net/manual/en/language.operators.bitwise.php – James Allardice Jun 06 '12 at 18:57 — James Allardice, Jun 06 '12 at 18:57

score 4 · Accepted Answer · answered Jun 06 '12 at 18:59

Those are Bitwise operators that allow evaluation and manipulation of specific bits within an integer.

$a | $b Or Bits that are set in either $a or $b are set.

$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")

score 3 · Answer 2 · answered Jun 06 '12 at 19:00

3

The literal answer can be found by reading about Bitwise Operators.

Practically speaking, it converts 3 values for Red, Blue and Green bytes into a single 24bit RGB value.

answered Jun 06 '12 at 19:00

Dancrumb

2 Answers2