So what you're saying is you want gmp to extend supporting factorials of real numbers, even though factorial is traditionally only defined for integers?

That would be great yeah

I disagree.  Factorial calculation *is* only valid for non-negative integers, the reason Google is able to give you an answer is, quite simply, because it's cheating.

The Gamma Function https://en.wikipedia.org/wiki/Gamma_function when provided with 1-shifted non-negative integers happens to produce the same results as the Factorial Function, however while the Gamma Function provides results for non-integer input, the Factorial Function does not.

libGMP side-steps this problem by only accepting integer inputs.  PHP has a bug in that it doesn't complain about receiving non-integer inputs, simply truncating them instead.

Moreover, since PHP's implementation of the GMP extension doesn't support floating point numbers, the only way this function could *appear* to work would be to first add support for foating point GMP values (no small task when you factor in the complications of which numeric type should and shouldn't be converted), THEN implement the Gamma Function ourselves.

The correct fix for this, IMO, is to raise a warning on receiving invalid input.

The fix for this bug has been committed.

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Thank you for the report, and for helping us make PHP better.