ldexp(3m) - osol9

1ldexp(3M)               Mathematical Library Functions               ldexp(3M)
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NAME

6       ldexp, ldexpf, ldexpl - load exponent of a floating point number
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SYNOPSIS

9       c99 [ flag... ] file... -lm [ library... ]
10       #include <math.h>
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12       double ldexp(double x, int exp);
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15       float ldexpf(float x, int exp);
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18       long double ldexpl(long double x, int exp);
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DESCRIPTION

22       These functions computes the quantity x* 2^exp.
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RETURN VALUES

25       Upon  successful  completion,  these functions return x multiplied by 2
26       raised to the power exp.
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29       If these functions would cause  overflow,  a  range  error  occurs  and
30       ldexp(),  ldexpf(),  and  ldexpl()  return  ±HUGE_VAL,  ±HUGE_VALF, and
31       ±HUGE_VALL (according to the sign of x), respectively.
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34       If x is NaN, a NaN is returned.
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37       If x is ±0 or ±Inf, x is returned.
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40       If exp  is 0, x is returned.
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ERRORS

43       These functions will fail if:
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45       Range Error    The result overflows.
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47                      If   the   integer   expression   (math_errhandling    &
48                      MATH_ERREXCEPT) is non-zero, the overflow floating-point
49                      exception is raised.
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51                      The ldexp() function sets errno to ERANGE if the  result
52                      overflows.
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USAGE

56       An  application  wanting to check for exceptions should call feclearex‐
57       cept(FE_ALL_EXCEPT) before  calling  these  functions.  On  return,  if
58       fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is
59       non-zero, an exception has been raised. An  application  should  either
60       examine the return value or check the floating point exception flags to
61       detect exceptions.
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64       An application can also set errno  to  0  before  calling  ldexp().  On
65       return,  if  errno is non-zero, an error has occurred. The ldexpf() and
66       ldexpl() functions do not set errno.
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ATTRIBUTES

69       See attributes(5) for descriptions of the following attributes:
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74       ┌─────────────────────────────┬─────────────────────────────┐
75       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
76       ├─────────────────────────────┼─────────────────────────────┤
77       │Interface Stability          │Standard                     │
78       ├─────────────────────────────┼─────────────────────────────┤
79       │MT-Level                     │MT-Safe                      │
80       └─────────────────────────────┴─────────────────────────────┘
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