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(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99
DESCRIPTION
The ldexp() function returns 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, 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.
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. | |
CONFORMING TO
C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89.
SEE ALSO
COLOPHON
This page is part of release 3.23 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/.
