 ldexp(3)  phpMan
LDEXP(3) Linux Programmer's Manual LDEXP(3)
NAME
ldexp, ldexpf, ldexpl  multiply floatingpoint number by integral power of 2
SYNOPSIS
#include <math.h>
double ldexp(double x, int exp);
float ldexpf(float x, int exp);
long double ldexpl(long double x, int exp);
Link with lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
ldexpf(), ldexpl():
_BSD_SOURCE  _SVID_SOURCE  _XOPEN_SOURCE >= 600  _ISOC99_SOURCE 
_POSIX_C_SOURCE >= 200112L;
or cc std=c99
DESCRIPTION
The ldexp() function returns the result of multiplying the floatingpoint 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 floatingpoint exception (FE_OVERFLOW) is
raised.
Range error, underflow
errno is set to ERANGE. An underflow floatingpoint exception (FE_UNDERFLOW) is
raised.
ATTRIBUTES
Multithreading (see pthreads(7))
The ldexp(), ldexpf(), and ldexpl() functions are threadsafe.
CONFORMING TO
C99, POSIX.12001. The variant returning double also conforms to SVr4, 4.3BSD, C89.
SEE ALSO
frexp(3), modf(3), scalbln(3)
COLOPHON
This page is part of release 3.74 of the Linux manpages project. A description of the
project, information about reporting bugs, and the latest version of this page, can be
found at http://www.kernel.org/doc/manpages/.
20130819 LDEXP(3)
