expl(3m) - osol9

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

6       exp, expf, expl - exponential function
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SYNOPSIS

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

22       These functions compute the base-e exponential of x.
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RETURN VALUES

25       Upon  successful  completion,  these  functions  return the exponential
26       value of x.
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29       If the correct value would cause overflow, a  range  error  occurs  and
30       exp(),  expf(),  and  expl() return HUGE_VAL, HUGE_VALF, and HUGE_VALL,
31       respectively.
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34       If x is NaN, a NaN is returned.
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37       If x is ±0, 1 is returned.
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40       If x is +Inf, x is returned.
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43       For exceptional cases, matherr(3M) tabulates the values to be  returned
44       by exp() as specified by SVID3 and XPG3. See standards(5).
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ERRORS

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

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

73       See attributes(5) for descriptions of the following attributes:
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78       ┌─────────────────────────────┬─────────────────────────────┐
79       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
80       ├─────────────────────────────┼─────────────────────────────┤
81       │Interface Stability          │Standard                     │
82       ├─────────────────────────────┼─────────────────────────────┤
83       │MT-Level                     │MT-Safe                      │
84       └─────────────────────────────┴─────────────────────────────┘
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