scalb(3m) - osol9

1scalb(3M)               Mathematical Library Functions               scalb(3M)
2
3
4

NAME

6       scalb,  scalbf, scalbl - load exponent of a radix-independent floating-
7       point number
8

SYNOPSIS

10       c99 [ flag... ] file... -lm [ library... ]
11       #include <math.h>
12
13       double scalb(double x, double n);
14
15
16       float scalbf(float x, float n);
17
18
19       long double scalbl(long double x, long double n);
20
21

DESCRIPTION

23       These functions compute x * r^n, where r is the radix of the  machine's
24       floating  point  arithmetic.  When  r  is  2,  scalb() is equivalent to
25       ldexp(3M). The value of r is FLT_RADIX which is defined in <float.h>.
26

RETURN VALUES

28       Upon successful completion, the scalb() function returns x * r^n.
29
30
31       If x or n is NaN, a NaN is returned.
32
33
34       If n is 0, x is returned.
35
36
37       If x is ±Inf and n is not −Inf, x is returned.
38
39
40       If x is ±0 and n is not +Inf, x is returned.
41
42
43       If x is ±0 and n is +Inf, a domain error occurs and a NaN is returned.
44
45
46       If x is ±Inf and n is  −Inf,  a  domain  error  occurs  and  a  NaN  is
47       returned.
48
49
50       If  the  result  would  cause  an  overflow,  a  range error occurs and
51       ±HUGE_VAL (according to the sign of x) is returned.
52
53
54       For exceptional cases, matherr(3M) tabulates the values to be  returned
55       by scalb() as specified by SVID3 and XPG3. See standards(5).
56

ERRORS

58       These functions will fail if:
59
60       Domain Error    If x is 0 and n is +Inf, or x is Inf and n is −Inf.
61
62                       If   the   integer   expression   (math_errhandling   &
63                       MATH_ERREXCEPT) is non-zero, then the invalid floating-
64                       point exception is raised.
65
66
67       Range Error     The result would overflow.
68
69                       If   the   integer   expression   (math_errhandling   &
70                       MATH_ERREXCEPT) is non-zero, then the  overflow  float‐
71                       ing-point exception is raised.
72
73

USAGE

75       An  application  wanting to check for exceptions should call feclearex‐
76       cept(FE_ALL_EXCEPT) before  calling  these  functions.  On  return,  if
77       fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is
78       non-zero, an exception has been raised. An  application  should  either
79       examine the return value or check the floating point exception flags to
80       detect exceptions.
81

ATTRIBUTES

83       See attributes(5) for descriptions of the following attributes:
84
85
86
87
88       ┌─────────────────────────────┬─────────────────────────────┐
89       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
90       ├─────────────────────────────┼─────────────────────────────┤
91       │Interface Stability          │See below.                   │
92       ├─────────────────────────────┼─────────────────────────────┤
93       │MT-Level                     │MT-Safe                      │
94       └─────────────────────────────┴─────────────────────────────┘
95
96
97       The scalb() function is Standard. The scalbf() and  scalbl()  functions
98       are Stable.
99