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_isunordered compares two double precision numbers to determine if they are unordered.
_isunorderedf compares two floating-point numbers to determine if they are unordered.
int __cdecl _isunordered( double arg1, double arg2 ); int __cdecl _isunorderedf( float arg1, float arg2 );
- [in] The value to be compared to arg2.
- [in] The value to be compared to arg1.
IEEE-754 floating-point comparison can have four separate result values: less-than, equal-to, greater-than or unordered.
The first three conditions can be tested using normal C operators, and this function is used to test for the last condition.
Two values are unordered if either is a NaN. This means that a NaN is not equal to any value, even itself.
The C++ compiler returns a bool value instead of an int.