exp(), expf(), expl()
Compute the exponential function of a number
Synopsis:
#include <math.h> double exp( double x ); float expf( float x ); long double expl( long double x );
Arguments:
- x
- The number for which you want to calculate the exponential.
Library:
libm
Use the -l m option to qcc to link against this library.
Description:
These functions compute the exponential function of x (e x ).
A range error occurs if the magnitude of x is too large.
Returns:
The exponential value of x. For a correct value that would cause an underflow, these functions return 0.0.
If an error occurs, these functions return 0, but this is also a valid
mathematical result.
If you want to check for errors, set
errno
to 0, call the function, and then check errno again.
These functions don't change errno if no errors occurred.
Examples:
#include <stdio.h> #include <math.h> #include <stdlib.h> int main( void ) { printf( "%f\n", exp(.5) ); return EXIT_SUCCESS; }
produces the output:
1.648721
Classification:
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |
Caveats:
The value of expm1(x) may be more accurate than exp(x) - 1.0 for small values of x.