ISGREATER(3)

NAME
1.30 `isgreater', `isgreaterequal', `isless', `islessequal', `islessgreater', and `isunordered'-comparison macros

SYNOPSIS
     #include <math.h>
     int isgreater(real-floating X, real-floating Y);
     int isgreaterequal(real-floating X, real-floating Y);
     int isless(real-floating X, real-floating Y);
     int islessequal(real-floating X, real-floating Y);
     int islessgreater(real-floating X, real-floating Y);
     int isunordered(real-floating X, real-floating Y);

DESCRIPTION
`isgreater', `isgreaterequal', `isless', `islessequal', `islessgreater', and `isunordered' are macros defined for use in comparing floating-point numbers without raising any floating-point exceptions.
   The relational operators (i.e. <, >, <=, and >=) 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 (i.e., if one or both of the arguments a NaN, the relationship is called unordered). The specified macros 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 shown, "real-floating" indicates that the argument is an expression of real floating type.
   Please note that saying that the macros do not raise floating-point exceptions, it is referring to the function that they are performing. It is certainly possible to give them an expression which causes an exception. For example: `NaN < 1.0'
     causes an "invalid" exception, `isless(NaN, 1.0)'
     does not, and `isless(NaN*0., 1.0)'
     causes an exception due to the "NaN*0.", but not from the
     resultant reduced comparison of isless(NaN, 1.0).

RETURNS
No floating-point exceptions are raised for any of the macros. The `isgreater' macro returns the value of (x) > (y). The `isgreaterequal' macro returns the value of (x) >= (y). The `isless' macro returns the value of (x) < (y). The `islessequal' macro returns the value of (x) <= (y). The `islessgreater' macro returns the value of (x) < (y) || (x) > (y). The `isunordered' macro returns 1 if either of its arguments is NaN and 0 otherwise.

PORTABILITY
C99, POSIX.

SEE ALSO
isgreater is part of the library. The full documentation for is maintained as a Texinfo manual. If info and are properly installed at your site, the command

    info

will give you access to the complete manual.