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isunordered (3)
  • isunordered (3) ( Solaris man: Библиотечные вызовы )
  • isunordered (3) ( FreeBSD man: Библиотечные вызовы )
  • isunordered (3) ( Русские man: Библиотечные вызовы )
  • >> isunordered (3) ( Linux man: Библиотечные вызовы )
  • isunordered (3) ( POSIX man: Библиотечные вызовы )
  •  

    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: _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99  

    DESCRIPTION

    The normal relation operations (like <, "less than") will fail if one of the operands is NaN. This will cause an exception. To avoid this, C99 defines these macros. The macros are guaranteed to evaluate their operands only once. The operands can be of any real floating-point type.
    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.  

    CONFORMING TO

    C99, POSIX.1-2001.  

    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 3.14 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    RETURN VALUE
    ERRORS
    CONFORMING TO
    NOTES
    SEE ALSO
    COLOPHON


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