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LDEXP(3) | Linux Programmer's Manual | LDEXP(3) |
NAME¶
ldexp, ldexpf, ldexpl - multiply floating-point number by integral power of 2SYNOPSIS¶
#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():
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).Interface | Attribute | Value |
ldexp (), ldexpf (), ldexpl () | 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 |