LDEXPSection: Linux Programmer's Manual (3)
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NAMEldexp, 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)):
DESCRIPTIONThe ldexp() function returns the result of multiplying the floating-point number x by 2 raised to the power exp.
RETURN VALUEOn 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.
ERRORSSee 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 TOC99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89.
SEE ALSOfrexp(3), modf(3), scalbln(3)
COLOPHONThis page is part of release 3.21 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/.