scalb(3) - f38

1scalb(3)                   Library Functions 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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LIBRARY

10       Math library (libm, -lm)
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SYNOPSIS

13       #include <math.h>
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15       [[deprecated]] double scalb(double x, double exp);
16       [[deprecated]] float scalbf(float x, float exp);
17       [[deprecated]] long double scalbl(long double x, long double exp);
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19   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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21       scalb():
22           _XOPEN_SOURCE >= 500
23               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
24               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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26       scalbf(), scalbl():
27           _XOPEN_SOURCE >= 600
28               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
29               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

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

40       On success, these functions return x * FLT_RADIX ** exp.
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42       If x or exp is a NaN, a NaN is returned.
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44       If  x is positive infinity (negative infinity), and exp is not negative
45       infinity, positive infinity (negative infinity) is returned.
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47       If x is +0 (-0), and exp is not positive infinity, +0 (-0) is returned.
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49       If x is zero, and exp is positive infinity, a domain error occurs,  and
50       a NaN is returned.
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52       If  x  is an infinity, and exp is negative infinity, a domain error oc‐
53       curs, and a NaN is returned.
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55       If the result overflows, a range error occurs, and the functions return
56       HUGE_VAL,  HUGE_VALF,  or HUGE_VALL, respectively, with a sign the same
57       as x.
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59       If the result underflows, a range error occurs, and the  functions  re‐
60       turn zero, with a sign the same as x.
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ERRORS

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

83       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
84       tributes(7).
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86       ┌────────────────────────────────────────────┬───────────────┬─────────┐
87       │Interface                                   │ Attribute     │ Value   │
88       ├────────────────────────────────────────────┼───────────────┼─────────┤
89       │scalb(), scalbf(), scalbl()                 │ Thread safety │ MT-Safe │
90       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

93       None.
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HISTORY

96       scalb()
97              4.3BSD.  Obsolescent in POSIX.1-2001; Removed  in  POSIX.1-2008,
98              recommending  the use of scalbln(3), scalblnf(3), or scalblnl(3)
99              instead.
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BUGS

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