ldexp(3)                   Library Functions Manual                   ldexp(3)

NAME
       ldexp, ldexpf, ldexpl - multiply floating-point number by integral
       power of 2

LIBRARY
       Math library (libm, -lm)

SYNOPSIS
       #include <math.h>

       double ldexp(double x, int exp);
       float ldexpf(float x, int exp);
       long double ldexpl(long double x, int exp);

   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 <= 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
       (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 |
       +--------------------------------------------+---------------+---------+
STANDARDS
       C11, POSIX.1-2008.

HISTORY
       C99, POSIX.1-2001.

       The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO
       frexp(3), modf(3), scalbln(3)

Linux man-pages 6.7               2023-10-31                          ldexp(3)