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isnan

From cppreference.com
< c‎ | numeric‎ | math
 
 
 
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isnan
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Macro constants
 
Defined in header <math.h>
#define isnan(arg) /* implementation defined */
(since C99)

Determines if the given floating point number arg is not-a-number (NaN). The macro returns an integral value.

Contents

[edit] Parameters

arg - floating point value

[edit] Return value

Nonzero integral value if arg is NaN, 0 otherwise.

[edit] Example

#include <stdio.h>
#include <math.h>
#include <float.h>
 
int main()
{
    printf("isnan(NAN)         = %d\n", isnan(NAN));
    printf("isnan(INFINITY)    = %d\n", isnan(INFINITY));
    printf("isnan(0.0)         = %d\n", isnan(0.0));
    printf("isnan(DBL_MIN/2.0) = %d\n", isnan(DBL_MIN/2.0));
    printf("isnan(1.0)         = %d\n", isnan(1.0));
 
    return 0;
}

Possible output:

isnan(NAN)         = 1
isnan(INFINITY)    = 0
isnan(0.0)         = 0
isnan(DBL_MIN/2.0) = 0
isnan(1.0)         = 0

[edit] See also

categorizes the given floating point value
(function) [edit]
checks if the given number has finite value
(function) [edit]
(C99)
checks if the given number is infinite
(function) [edit]
checks if the given number is normal
(function) [edit]