Will a C conditional always return 1 or 0?

Question

Do C conditional statements always return [1 or 0], or do they return [0 or 'something other than zero']. I ask because:

pseudo code -

foo(address, shouldSend):
register >>= 1
register <<= 1 // to clear bit in first position
register |= shouldSend // to signal whether it should send or not

the problem occurs if somebody passin IN a shouldSend value of true greater than one (as only 0 is false and all else is true, technically this is valid). since i am directly OR'ing the truth value of shouldSend with the register, it better not be say 0xFF! i already have a solution, so the question is more for curiousity sake. i am wondering though if:

foo(address, shouldSend):
register >>= 1
register <<= 1 // to clear bit in first position
register |= (shouldSend > 0) // to signal whether it should send or not

solves the problem? i would think that now the problem of an 0xFF(or in general, something greater than 1) passed in is masked by the C conditional. but this only holds IF C conditionals are guaranteed to return [0 or 1].

ps - i also realize that it is probably compiler dependent, but what does the ansi standard say about this?

Answer 1

Standard specifies that the result is always integer value equals to 0 or 1

6.5.8 Relational operators

Each of the operators < (less than), > (greater than), <= (less than or equal to), and >= (greater than or equal to) shall yield 1 if the specified relation is true and 0 if it is false.92) The result has type int.

Answer 2

Doesn't matter if it is specified or not. It is best to always test against false and be explicit about your or-equals values. This removes any worry about compiler implementations and is clearer and more maintainable.