scalbn(3)

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

6       scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl - multiply float‐
7       ing-point number by integral power of radix
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SYNOPSIS

10       #include <math.h>
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12       double scalbln(double x, long exp);
13       float scalblnf(float x, long exp);
14       long double scalblnl(long double x, long exp);
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16       double scalbn(double x, int exp);
17       float scalbnf(float x, int exp);
18       long double scalbnl(long double x, int exp);
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20       Link with -lm.
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22   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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24       scalbln(), scalblnf(), scalblnl():
25              _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
26                  || /* Since glibc 2.19: */ _DEFAULT_SOURCE
27       scalbn(), scalbnf(), scalbnl():
28              _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
29                  || /* Since glibc 2.19: */ _DEFAULT_SOURCE
30                  || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

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

41       On success, these functions return x * FLT_RADIX ** exp.
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43       If x is a NaN, a NaN is returned.
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45       If x is positive infinity (negative infinity), positive infinity (nega‐
46       tive infinity) is returned.
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48       If x is +0 (-0), +0 (-0) is returned.
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50       If the result overflows, a range error occurs, and the functions return
51       HUGE_VAL,  HUGE_VALF,  or HUGE_VALL, respectively, with a sign the same
52       as x.
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54       If the result underflows, a range error occurs, and the  functions  re‐
55       turn zero, with a sign the same as x.
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ERRORS

58       See  math_error(7) for information on how to determine whether an error
59       has occurred when calling these functions.
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61       The following errors can occur:
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63       Range error, overflow
64              An overflow floating-point exception (FE_OVERFLOW) is raised.
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66       Range error, underflow
67              errno is set to ERANGE.  An underflow  floating-point  exception
68              (FE_UNDERFLOW) is raised.
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VERSIONS

71       These functions first appeared in glibc in version 2.1.
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ATTRIBUTES

74       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
75       tributes(7).
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77       ┌──────────────────────────────────┬───────────────┬─────────┐
78       │Interface                         │ Attribute     │ Value   │
79       ├──────────────────────────────────┼───────────────┼─────────┤
80       │scalbn(), scalbnf(), scalbnl(),   │ Thread safety │ MT-Safe │
81       │scalbln(), scalblnf(), scalblnl() │               │         │
82       └──────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

84       C99, POSIX.1-2001, POSIX.1-2008.
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NOTES

87       These  functions  differ  from  the  obsolete  functions  described  in
88       scalb(3) in the type of their second argument.  The functions described
89       on this page have a second argument of an integral type, while those in
90       scalb(3) have a second argument of type double.
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92       If  FLT_RADIX equals 2 (which is usual), then scalbn() is equivalent to
93       ldexp(3).
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BUGS

96       Before glibc 2.20, these functions did not set errno for range errors.
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COLOPHON

102       This page is part of release 5.10 of the Linux  man-pages  project.   A
103       description  of  the project, information about reporting bugs, and the
104       latest    version    of    this    page,    can     be     found     at
105       https://www.kernel.org/doc/man-pages/.
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109                                  2020-11-01                        SCALBLN(3)