PHP function flags, how?

[peRpLeX]

I'm attempting to create a function with flags as its arguments but the output is always different with what's expected :\[code\]define("FLAG_A", 1); define("FLAG_B", 4); define("FLAG_C", 7); function test_flags($flags) { if($flags & FLAG_A) echo "A"; if($flags & FLAG_B) echo "B"; if($flags & FLAG_C) echo "C"; } test_flags(FLAG_B | FLAG_C); # Output is always ABC, not BC \[/code\]How can I fix this problem?