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fpclassify

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

Categorizes floating point value arg into the following categories: zero, subnormal, normal, infinite, NAN, or implementation-defined category. The macro returns an integral value.

Contents

[edit] Parameters

arg - floating point value

[edit] Return value

One of FP_INFINITE, FP_NAN, FP_NORMAL, FP_SUBNORMAL, FP_ZERO or implementation-defined type, specifying the category of arg.

[edit] Example

#include <stdio.h>
#include <math.h>
#include <float.h>
 
int main()
{
    printf("FP_NAN       = %d\n", FP_NAN);         // 0
    printf("FP_INFINITE  = %d\n", FP_INFINITE);    // 1
    printf("FP_ZERO      = %d\n", FP_ZERO);        // 2
    printf("FP_SUBNORMAL = %d\n", FP_SUBNORMAL);   // 3
    printf("FP_NORMAL    = %d\n", FP_NORMAL);      // 4
    printf("\n");
 
    printf("fpclassify(NAN)         = %d\n", fpclassify(NAN));           // 0
    printf("fpclassify(INFINITY)    = %d\n", fpclassify(INFINITY));      // 1
    printf("fpclassify(0.0)         = %d\n", fpclassify(0.0));           // 2
    printf("fpclassify(DBL_MIN/2.0) = %d\n", fpclassify(DBL_MIN/2.0));   // 3
    printf("fpclassify(1.0)         = %d\n", fpclassify(1.0));           // 4
 
    return 0;
}

Possible output:

FP_NAN       = 0
FP_INFINITE  = 1
FP_ZERO      = 2
FP_SUBNORMAL = 3
FP_NORMAL    = 4
 
fpclassify(NAN)         = 0
fpclassify(INFINITY)    = 1
fpclassify(0.0)         = 2
fpclassify(DBL_MIN/2.0) = 3
fpclassify(1.0)         = 4

[edit] See also

checks if the given number has finite value
(function) [edit]
(C99)
checks if the given number is infinite
(function) [edit]
(C99)
checks if the given number is NaN
(function) [edit]
checks if the given number is normal
(function) [edit]
C++ documentation for fpclassify