scalbf(3)

1SCALB(3)                   Linux Programmer's Manual                  SCALB(3)
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NAME

6       scalb,  scalbf,  scalbl  -  multiply  floating-point number by integral
7       power of radix (OBSOLETE)
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SYNOPSIS

10       #include <math.h>
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12       double scalb(double x, double exp);
13       float scalbf(float x, float exp);
14       long double scalbl(long double x, long double exp);
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16       Link with -lm.
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18   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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20       scalb():
21           _XOPEN_SOURCE >= 500
22               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
23               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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25       scalbf(), scalbl():
26           _XOPEN_SOURCE >= 600
27               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
28               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

31       These functions multiply their first argument x by FLT_RADIX  (probably
32       2) to the power of exp, that is:
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34           x * FLT_RADIX ** exp
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36       The definition of FLT_RADIX can be obtained by including <float.h>.
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RETURN VALUE

39       On success, these functions return x * FLT_RADIX ** exp.
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41       If x or exp is a NaN, a NaN is returned.
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43       If  x is positive infinity (negative infinity), and exp is not negative
44       infinity, positive infinity (negative infinity) is returned.
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46       If x is +0 (-0), and exp is not positive infinity, +0 (-0) is returned.
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48       If x is zero, and exp is positive infinity, a domain error occurs,  and
49       a NaN is returned.
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51       If  x  is an infinity, and exp is negative infinity, a domain error oc‐
52       curs, and a NaN is returned.
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54       If the result overflows, a range error occurs, and the functions return
55       HUGE_VAL,  HUGE_VALF,  or HUGE_VALL, respectively, with a sign the same
56       as x.
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58       If the result underflows, a range error occurs, and the  functions  re‐
59       turn zero, with a sign the same as x.
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ERRORS

62       See  math_error(7) for information on how to determine whether an error
63       has occurred when calling these functions.
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65       The following errors can occur:
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67       Domain error: x is 0, and exp is positive infinity, or  x  is  positive
68       infinity  and  exp is negative infinity and the other argument is not a
69       NaN
70              errno is set  to  EDOM.   An  invalid  floating-point  exception
71              (FE_INVALID) is raised.
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73       Range error, overflow
74              errno  is  set  to ERANGE.  An overflow floating-point exception
75              (FE_OVERFLOW) is raised.
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77       Range error, underflow
78              errno is set to ERANGE.  An underflow  floating-point  exception
79              (FE_UNDERFLOW) is raised.
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ATTRIBUTES

82       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
83       tributes(7).
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85       ┌────────────────────────────────────────────┬───────────────┬─────────┐
86       │Interface                                   │ Attribute     │ Value   │
87       ├────────────────────────────────────────────┼───────────────┼─────────┤
88       │scalb(), scalbf(), scalbl()                 │ Thread safety │ MT-Safe │
89       └────────────────────────────────────────────┴───────────────┴─────────┘
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CONFORMING TO

92       scalb()  is  specified  in  POSIX.1-2001,   but   marked   obsolescent.
93       POSIX.1-2008 removes the specification of scalb(), recommending the use
94       of scalbln(3), scalblnf(3), or scalblnl(3) instead.  The scalb()  func‐
95       tion is from 4.3BSD.
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97       scalbf()  and  scalbl()  are  unstandardized;  scalbf() is nevertheless
98       present on several other systems
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BUGS

101       Before glibc 2.20, these functions did not set  errno  for  domain  and
102       range errors.
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COLOPHON

108       This  page  is  part of release 5.13 of the Linux man-pages project.  A
109       description of the project, information about reporting bugs,  and  the
110       latest     version     of     this    page,    can    be    found    at
111       https://www.kernel.org/doc/man-pages/.
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115                                  2021-03-22                          SCALB(3)