7.12.14 Comparison macros

• 7.12.14.1 The isgreater macro
• 7.12.14.2 The isgreaterequal macro
• 7.12.14.3 The isless macro
• 7.12.14.4 The islessequal macro
• 7.12.14.5 The islessgreater macro
• 7.12.14.6 The isunordered macro

1

The relational and equality operators support the usual mathematical relationships between numeric values. For any ordered pair of numeric values exactly one of the relationships – less, greater, and equal – is true. Relational operators may raise the “invalid” floating-point exception when argument values are NaNs. For a NaN and a numeric value, or for two NaNs, just the unordered relationship is true.[1] The following subclauses provide macros that are quiet (non floating-point exception raising) versions of the relational operators, and other comparison macros that facilitate writing efficient code that accounts for NaNs without suffering the “invalid” floating-point exception. In the synopses in this subclause, real-floating indicates that the argument shall be an expression of real floating type.

Footnotes

[1]

IEC 60559 requires that the built-in relational operators raise the “invalid” floating-point exception if the operands compare unordered, as an error indicator for programs written without consideration of NaNs; the result in these cases is false.