Tribblix: manual page: ldexp.3m

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
feclearexcept(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