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NAMEexp , expf ,
expl , exp2 ,
exp2f , exp2l ,
expm1 , expm1f ,
expm1l , pow ,
powf , powl —
exponential and power functions
LIBRARYMath Library (libm, -lm)SYNOPSIS#include <math.h>
double
float
long double
double
float
long double
double
float
long double
double
float
long double
DESCRIPTIONTheexp (), expf (), and
expl () functions compute the base
e exponential value of the given argument
x.
The The The ERROR (due to Roundoff etc.)The values ofexp (0),
expm1 (0),
exp2 (integer), and
pow (integer,
integer) are exact provided that they are representable.
Otherwise the error in these functions is generally below one
ulp.
RETURN VALUESThese functions will return the appropriate computation unless an error occurs or an argument is out of range. The functionspow (x, y),
powf (x,
y), and
powl (x, y)
raise an invalid exception and return an NaN if x < 0
and y is not an integer.
NOTESThe functionpow (x,
0) returns x**0 = 1 for all x including x = 0, infinity,
and NaN . Previous implementations of pow may have defined x**0 to be
undefined in some or all of these cases. Here are reasons for returning x**0 =
1 always:
SEE ALSOclog(3), cpow(3), fenv(3), ldexp(3), log(3), math(3)STANDARDSThese functions conform to ISO/IEC 9899:1999 (“ISO C99”).HISTORYTheexp () function appeared in
Version 1 AT&T UNIX.
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