| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | SEE ALSO | COLOPHON | The Linux Programming Interface |
LDEXP(3) Linux Programmer's Manual LDEXP(3)
ldexp, ldexpf, ldexpl - multiply floating-point number by integral power of 2
#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
The ldexp() function returns the result of multiplying the floating-point
number x by 2 raised to the power exp.
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, an 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.
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.
C99, POSIX.1-2001. The variant returning double also conforms to SVr4,
4.3BSD, C89.
frexp(3), modf(3), scalbln(3)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
2010-09-20 LDEXP(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface