NAME
ldexp, ldexpf,
ldexpl —
multiply floating-point number by
integral power of 2
LIBRARY
library “libm”
SYNOPSIS
#include
<math.h>
double
ldexp(double
x, int exp);
float
ldexpf(float
x, int exp);
long double
ldexpl(long
double x, int
exp);
DESCRIPTION
Theldexp()
family of functions compute
x * 2^exp
for a real floating-point number x.
RETURN VALUES
The functions return the value of x times 2 raised to the power exp. Otherwise the following may occur:
- If x is NaN, a NaN is returned.
- If exp is zero or x is either ± 0 or ±∞, x is returned.
- If the call would cause an overflow, a range error occurs and either
±HUGE_VAL,±HUGE_VALF, or±HUGE_VALLis returned, depending on the sign of x and the type of the return value. - If an underflow would be caused by the correct value, and the value is not representable, either 0.0 or an implementation-defined value is returned.
SEE ALSO
STANDARDS
The described functions conform to ISO/IEC 9899:1999 (“ISO C99”).