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man:ldexpl

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)
/data/webs/external/dokuwiki/data/pages/man/ldexpl.txt · Last modified: 2019/05/17 09:32 by 127.0.0.1

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