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signed zero

Floats have both +0 and -0; they compare equal, but some results (like 1 / -0) tell them apart.

IEEE 754 encodes +0 and -0 with exponent and fraction all zeros and differing sign bits; they compare equal, yet division by them, copysign and some library functions distinguish them.

Examples

  • -0.0f is 0x80000000. It compares equal to 0.0f, but 1 / −0.0 is −∞.

See also

IEEE 754 floating-point infinity
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