scalbn(3)

1scalbln(3)                 Library Functions 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
8

LIBRARY

10       Math library (libm, -lm)
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SYNOPSIS

13       #include <math.h>
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15       double scalbln(double x, long exp);
16       float scalblnf(float x, long exp);
17       long double scalblnl(long double x, long exp);
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19       double scalbn(double x, int exp);
20       float scalbnf(float x, int exp);
21       long double scalbnl(long double x, int exp);
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23   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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25       scalbln(), scalblnf(), scalblnl():
26           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
27               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
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29       scalbn(), scalbnf(), scalbnl():
30           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
31               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
32               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

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

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

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

73       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
74       tributes(7).
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76       ┌────────────────────────────────────────────┬───────────────┬─────────┐
77       │Interface                                   │ Attribute     │ Value   │
78       ├────────────────────────────────────────────┼───────────────┼─────────┤
79       │scalbn(), scalbnf(), scalbnl(), scalbln(),  │ Thread safety │ MT-Safe │
80       │scalblnf(), scalblnl()                      │               │         │
81       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

84       C11, POSIX.1-2008.
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HISTORY

87       glibc 2.1.  C99, POSIX.1-2001.
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HISTORY

90       These  functions  differ  from  the  obsolete  functions  described  in
91       scalb(3) in the type of their second argument.  The functions described
92       on this page have a second argument of an integral type, while those in
93       scalb(3) have a second argument of type double.
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NOTES

96       If FLT_RADIX equals 2 (which is usual), then scalbn() is equivalent  to
97       ldexp(3).
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BUGS

100       Before glibc 2.20, these functions did not set errno for range errors.
101