Defined in header <math.h> | ||
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#define signbit( arg ) /* implementation defined */ | (since C99) |
Determines if the given floating point number arg is negative. The macro returns an integral value.
| arg | - | floating point value |
Nonzero integral value if arg is negative, 0 otherwise.
This macro detects the sign bit of zeroes, infinities, and NaNs. Along with copysign, this macro is one of the only two portable ways to examine the sign of a NaN.
#include <math.h>
#include <stdio.h>
int main(void)
{
printf("signbit(+0.0) = %d\n", signbit(+0.0));
printf("signbit(-0.0) = %d\n", signbit(-0.0));
}Possible output:
signbit(+0.0) = 0 signbit(-0.0) = 128
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(C99)(C99) | computes absolute value of a floating-point value (\(\small{|x|}\)|x|) (function) |
|
(C99)(C99)(C99) | produces a value with the magnitude of a given value and the sign of another given value (function) |
C++ documentation for signbit |
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