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 NAME     
 |  |  |  | NaN, Inf, isNaN, isInf – not-a-number and infinity functions 
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 SYNOPSIS     
 |  |  |  | #include <u.h> #include <libc.h> 
    
    
    double NaN(void) 
    
    
    double Inf(int) 
    
    
    int     isNaN(double) 
    
    
    int     isInf(double, int)
 
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 DESCRIPTION     
 |  |  |  | The IEEE floating point standard defines values called ‘not-a-number’
    and positive and negative ‘infinity’. These values can be produced
    by such things as overflow and division by zero. Also, the library
    functions sometimes return them when the arguments are not in
    the domain, or the result is out of range. 
    
    
    NaN returns a double that is not-a-number. IsNaN returns true
    if its argument is not-a-number. 
    
    
    Inf(i) returns positive infinity if i is greater than or equal
    to zero, else negative infinity. IsInf returns true if its first
    argument is infinity with the same sign as the second argument. 
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 SOURCE     
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