man:ldexpf
LDEXP(3) Linux Programmer's Manual LDEXP(3)
NAME
ldexp, ldexpf, ldexpl - multiply floating-point 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(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 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 (nega- tive 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).
allbox; lbw27 lb lb l l l. Interface Attribute Value T{ ldexp(),
ldexpf(), ldexpl() T} Thread safety MT-Safe
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
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 4.16 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
2017-09-15 LDEXP(3)
/home/gen.uk/domains/wiki.gen.uk/public_html/data/pages/man/ldexpf.txt · Last modified: 2019/05/17 09:32 by 127.0.0.1