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man:isgreaterequal

ISGREATER(3) Linux Programmer's Manual ISGREATER(3)

NAME

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

SYNOPSIS

     #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);
     Link with -lm.
 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
     All functions described here:
            _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

DESCRIPTION

     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  inte-
     ger  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

     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

     No errors occur.

ATTRIBUTES

     For  an  explanation  of  the  terms  used   in   this   section,   see
     attributes(7).
     allbox; lbw30 lb lb l l l.  Interface Attribute Value T{ isgreater(),
     isgreaterequal(), isless(), islessequal(), islessgreater(),
     isunordered() T}   Thread safety  MT-Safe

CONFORMING TO

     POSIX.1-2001, POSIX.1-2008, C99.

NOTES

     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.

SEE ALSO

     fpclassify(3), isnan(3)

COLOPHON

     This page is part of release 4.16 of the Linux  man-pages  project.   A
     description  of  the project, information about reporting bugs, and the
     latest    version    of    this    page,    can     be     found     at
     https://www.kernel.org/doc/man-pages/.
                                2017-09-15                      ISGREATER(3)
/data/webs/external/dokuwiki/data/pages/man/isgreaterequal.txt · Last modified: 2019/05/17 09:32 by 127.0.0.1

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