copysign, copysignf, copysignl
From cppreference.com
Defined in header <math.h>
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float copysignf( float x, float y ); |
(1) | (since C99) |
double copysign( double x, double y ); |
(2) | (since C99) |
long double copysignl( long double x, long double y ); |
(3) | (since C99) |
Defined in header <tgmath.h>
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#define copysign(from, to) |
(7) | (since C99) |
1-3) Composes a floating point value with the magnitude of
x
and the sign of y
. 4) Type-generic macro: If any argument has type long double,
copysignl
is called. Otherwise, if any argument has integer type or has type double, copysign
is called. Otherwise, copysignf
is called.Parameters
x, y | - | floating point values |
Return value
If no errors occur, the floating point value with the magnitude of x
and the sign of y
is returned.
If x
is NaN, then NaN with the sign of y
is returned.
If y
is -0, the result is only negative if the implementation supports the signed zero consistently in arithmetic operations.
Error handling
This function is not subject to any errors specified in math_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
- The returned value is exact (FE_INEXACT is never raised) and independent of the current rounding mode.
Notes
copysign
is the only portable way to manipulate the sign of a NaN value (to examine the sign of a NaN, signbit may also be used).