exp2, exp2f, exp2l

Parameters

Return value

If no errors occur, the base- 2 exponential of n ( 2 n ) 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.

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

Example

#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");
}

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

References

See also