Format
#include <math.h> double log(double x);
Language Level: ANSI
Threadsafe: Yes.
Description
The log() function calculates the natural logarithm (base e) of x.
Return Value
The log() function returns the computed value. If x is negative, log()sets errno to EDOM and may return the value -HUGE_VAL. If x is zero, log() returns the value -HUGE_VAL, and may set errno to ERANGE.
Example that uses log()
This example calculates the natural logarithm of 1000.0.
#include <math.h> #include <stdio.h> int main(void) { double x = 1000.0, y; y = log(x); printf("The natural logarithm of %lf is %lf\n", x, y); } /******************** Output should be similar to: ************** The natural logarithm of 1000.000000 is 6.907755 */
Related Information
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