isgreater(3) - Linux manual page (original) (raw)

isgreater(3) Library Functions Manual isgreater(3)

NAME top

   isgreater, isgreaterequal, isless, islessequal, islessgreater,
   isunordered - floating-point relational tests without exception
   for NaN

LIBRARY top

   Math library (_libm_, _-lm_)

SYNOPSIS top

   **#include <math.h>**

   **int isgreater(**_x_**,** _y_**);**
   **int isgreaterequal(**_x_**,** _y_**);**
   **int isless(**_x_**,** _y_**);**
   **int islessequal(**_x_**,** _y_**);**
   **int islessgreater(**_x_**,** _y_**);**
   **int isunordered(**_x_**,** _y_**);**

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       All functions described here:
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

DESCRIPTION top

   The normal relational operations (like **<**, "less than") fail if one
   of the operands is NaN.  This will cause an exception.  To avoid
   this, C99 defines the macros listed below.

   These macros are guaranteed to evaluate their arguments only once.
   The arguments must be of real floating-point type (note: do not
   pass integer values as arguments to these macros, since the
   arguments will _not_ be promoted to real-floating types).

   **isgreater**()
          determines _(x) > (y)_ without an exception if _x_ or _y_ is NaN.

   **isgreaterequal**()
          determines _(x) >= (y)_ without an exception if _x_ or _y_ is
          NaN.

   **isless**()
          determines _(x) < (y)_ without an exception if _x_ or _y_ is NaN.

   **islessequal**()
          determines _(x) <= (y)_ without an exception if _x_ or _y_ is
          NaN.

   **islessgreater**()
          determines _(x) < (y) || (x) > (y)_ without an exception if _x_
          or _y_ is NaN.  This macro is not equivalent to _x != y_
          because that expression is true if _x_ or _y_ is NaN.

   **isunordered**()
          determines whether its arguments are unordered, that is,
          whether at least one of the arguments is a NaN.

RETURN VALUE top

   The macros other than **isunordered**() return the result of the
   relational comparison; these macros return 0 if either argument is
   a NaN.

   **isunordered**() returns 1 if _x_ or _y_ is NaN and 0 otherwise.

ERRORS top

   No errors occur.

ATTRIBUTES top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌──────────────────────────────────────┬───────────────┬─────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├──────────────────────────────────────┼───────────────┼─────────┤
   │ **isgreater**(), **isgreaterequal**(),       │ Thread safety │ MT-Safe │
   │ **isless**(), **islessequal**(),             │               │         │
   │ **islessgreater**(), **isunordered**()       │               │         │
   └──────────────────────────────────────┴───────────────┴─────────┘

VERSIONS top

   Not all hardware supports these functions, and where hardware
   support isn't provided, they will be emulated by macros.  This
   will result in a performance penalty.  Don't use these functions
   if NaN is of no concern for you.

STANDARDS top

   C11, POSIX.1-2008.

HISTORY top

   POSIX.1-2001, C99.

SEE ALSO top

   [fpclassify(3)](../man3/fpclassify.3.html), [isnan(3)](../man3/isnan.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 isgreater(3)

Pages that refer to this page:fpclassify(3), math_error(7)