exp2, exp2f, exp2l
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Defined in header
<math.h>
float exp2f( float n );
(1)
(since C99)
double exp2( double n );
(2)
(since C99)
long double exp2l( long double n );
(3)
(since C99)
Defined in header
<tgmath.h>
#define exp2( n )
(4)
(since C99)
1-3) Computes 2 raised to the given power
n.4) Type-generic macro: If
n has type long double, exp2l is called. Otherwise, if n has integer type or the type double, exp2 is called. Otherwise, exp2f is called.[edit] Parameters
n
-
floating-point value
[edit] Return value
If no errors occur, the base-2 exponential of n (2n
) is returned.
If a range error due to overflow occurs, +HUGE_VAL , +HUGE_VALF, or +HUGE_VALL is returned.
If a range error occurs due to underflow, the correct result (after rounding) is returned.
[edit] Error handling
Errors are reported as specified in math_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
- If the argument is ±0, 1 is returned
- If the argument is -∞, +0 is returned
- If the argument is +∞, +∞ is returned
- If the argument is NaN, NaN is returned
[edit] Example
Run this code
#include <errno.h> #include <fenv.h> #include <float.h> #include <math.h> #include <stdio.h> // #pragma STDC FENV_ACCESS ON int main(void) { printf ("exp2(5) = %f\n", exp2(5)); printf ("exp2(0.5) = %f\n", exp2(0.5)); printf ("exp2(-4) = %f\n", exp2(-4)); // special values printf ("exp2(-0.9) = %f\n", exp2(-0.9)); printf ("exp2(-Inf) = %f\n", exp2(-INFINITY)); //error handling errno = 0; feclearexcept (FE_ALL_EXCEPT ); printf ("exp2(1024) = %f\n", exp2(1024)); if (errno == ERANGE ) perror (" errno == ERANGE"); if (fetestexcept (FE_OVERFLOW )) puts (" FE_OVERFLOW raised"); }
Possible output:
exp2(5) = 32.000000 exp2(0.5) = 1.414214 exp2(-4) = 0.062500 exp2(-0.9) = 0.535887 exp2(-Inf) = 0.000000 exp2(1024) = Inf errno == ERANGE: Result too large FE_OVERFLOW raised
[edit] References
- C23 standard (ISO/IEC 9899:2024):
- 7.12.6.2 The exp2 functions (p: TBD)
- 7.25 Type-generic math <tgmath.h> (p: TBD)
- F.10.3.2 The exp2 functions (p: TBD)
- C17 standard (ISO/IEC 9899:2018):
- 7.12.6.2 The exp2 functions (p: 177)
- 7.25 Type-generic math <tgmath.h> (p: 272-273)
- F.10.3.2 The exp2 functions (p: 379)
- C11 standard (ISO/IEC 9899:2011):
- 7.12.6.2 The exp2 functions (p: 242-243)
- 7.25 Type-generic math <tgmath.h> (p: 373-375)
- F.10.3.2 The exp2 functions (p: 521)
- C99 standard (ISO/IEC 9899:1999):
- 7.12.6.2 The exp2 functions (p: 223)
- 7.22 Type-generic math <tgmath.h> (p: 335-337)
- F.9.3.2 The exp2 functions (p: 458)
[edit] See also
(C99)(C99)(C99)
(function) [edit]
C++ documentation for exp2