ldexp(3M) Mathematical Library Functions ldexp(3M)NAME
ldexp, ldexpf, ldexpl - load exponent of a floating point number
SYNOPSIS
c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
double ldexp(double x, int exp);
float ldexpf(float x, int exp);
long double ldexpl(long double x, int exp);
DESCRIPTION
These functions computes the quantity x* 2**exp.
RETURN VALUES
Upon successful completion, these functions return x multiplied by 2
raised to the power exp.
If these functions would cause overflow, a range error occurs and
ldexp(), ldexpf(), and ldexpl() return ±HUGE_VAL, ±HUGE_VALF, and
±HUGE_VALL (according to the sign of x), respectively.
If x is NaN, a NaN is returned.
If x is ±0 or ±Inf, x is returned.
If exp is 0, x is returned.
ERRORS
These functions will fail if:
Range Error The result overflows.
If the integer expression (math_errhandling &
MATH_ERREXCEPT) is non-zero, the overflow floating-
point exception is raised.
The ldexp() function sets errno to ERANGE if the result
overflows.
USAGE
An application wanting to check for exceptions should call feclearex‐
cept(FE_ALL_EXCEPT) before calling these functions. On return, if
fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is
non-zero, an exception has been raised. An application should either
examine the return value or check the floating point exception flags to
detect exceptions.
An application can also set errno to 0 before calling ldexp(). On
return, if errno is non-zero, an error has occurred. The ldexpf() and
ldexpl() functions do not set errno.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOfrexp(3M), isnan(3M), modf(3M), attributes(5), standards(5)SunOS 5.10 12 Jul 2006 ldexp(3M)