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# signbit

From cppreference.com
< c‎ | numeric‎ | math

Defined in header `<math.h>` |  |
#define signbit(arg) /* implementation defined */ |  | (since C99)

Determines if the given floating point number `arg` is negative. The macro returns an integral value.

### [edit] Parameters

arg | - | floating point value

### [edit] Return value

Nonzero integral value if `arg` is negative, ​0​ otherwise

### [edit] Example

Run this code

    #include <stdio.h>
    #include <math.h>
    #include <float.h>

    int main(void)
    {
        printf("signbit(+0.0) = %d\n", signbit(+0.0));
        printf("signbit(-0.0) = %d\n", signbit(-0.0));

        return 0;
    }

Possible output:

    signbit(+0.0) = 0
    signbit(-0.0) = 128

### [edit] See also

fabsfabsffabsl (C99)(C99) | computes absolute value of a floating-point value (|x|) (function) [edit]
copysigncopysignfcopysignl (C99)(C99)(C99) | produces a value with the magnitude of a given value and the sign of another given value (function) [edit]
C++ documentation for signbit

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