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| ldexp |
| Portability: | ISO/ANSI C conforming, UNIX compatible |
| SYNOPSIS | |
| DESCRIPTION | |
| RETURN VALUE | |
| DIAGNOSTICS | |
| USAGE NOTES | |
| RELATED FUNCTIONS | |
| SEE ALSO |
| SYNOPSIS |
#include <math.h> double ldexp (double y, int i);
| DESCRIPTION |
ldexp
calculates y * 2i.
| RETURN VALUE |
ldexp
returns the value of type
double
that results
from the calculation.
| DIAGNOSTICS |
If the return value cannot be represented,
a warning message is sent to the standard error file (
stderr
). ±
HUGE_VAL
is
returned if an overflow occurs; 0 is returned if an underflow occurs.
| USAGE NOTES |
When used with
frexp
, the
ldexp
function is useful
in situations that require repeated multiplication by 2. If the next multiplication
causes an overflow or underflow, use
frexp
to separate the mantissa from the exponent. This gives you complete control
over the exponent and the mantissa, so you can operate on them separately
without any loss of precision. When you are finished, use
ldexp
to combine the mantissa and exponent again.
| RELATED FUNCTIONS |
| SEE ALSO |
|
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Copyright © 2001 by SAS Institute Inc., Cary, NC, USA. All rights reserved.