Man page - ldexpl(3)

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Manual

ldexp

NAME
LIBRARY
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
STANDARDS
HISTORY
SEE ALSO

NAME

ldexp, ldexpf, ldexpl - multiply floating-point number by integral power of 2

LIBRARY

Math library ( libm , -lm )

SYNOPSIS

#include <math.h>

double ldexp(double x , int exp );
float ldexpf(float x , int exp );
long double ldexpl(long double x , int exp );

Feature Test Macro Requirements for glibc (see feature_test_macros (7)):

ldexpf (), ldexpl ():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

These functions return the result of multiplying the floating-point number x by 2 raised to the power exp .

RETURN VALUE

On success, these functions return x * (2^exp) .

If exp is zero, then x is returned.

If x is a NaN, a NaN is returned.

If x is positive infinity (negative infinity), positive infinity (negative infinity) is returned.

If the result underflows, a range error occurs, and zero is returned.

If the result overflows, a range error occurs, and the functions return HUGE_VAL , HUGE_VALF , or HUGE_VALL , respectively, with a sign the same as x .

ERRORS

See math_error (7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:
Range error, overflow

errno is set to ERANGE . An overflow floating-point exception ( FE_OVERFLOW ) is raised.

Range error, underflow

errno is set to ERANGE . An underflow floating-point exception ( FE_UNDERFLOW ) is raised.

ATTRIBUTES

For an explanation of the terms used in this section, see attributes (7).

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STANDARDS

C11, POSIX.1-2008.

HISTORY

C99, POSIX.1-2001.

The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO

frexp (3), modf (3), scalbln (3)