exp(3m)
NAME
exp, log, log10, pow, sqrt − exponential, logarithm, power, square root functions
SYNTAX
#include <math.h>
double exp(x)
double x;
double log(x)
double x;
double log10(x)
double x;
double pow(x, y)
double x, y;
double sqrt(x)
double x;
DESCRIPTION
The exp function returns ex.
The log function returns the natural logarithm of x. The value of x must be positive.
The log10 function returns the logarithm base ten of x. The value of x must be positive.
The pow function returns xy. If x is zero, y must be positive. If x is negative, y must be an integer.
The sqrt function returns the non-negative square root of x. The value of x may not be negative.
DIAGNOSTICS
The exp function returns HUGE when the correct value would overflow, or 0 when the correct value would underflow, and sets errno to ERANGE.
The log and log10 functions return −HUGE and set errno to EDOM when x is non-positive. A message indicating DOMAIN error (or SING error when x is 0) is printed on the standard error output.
The pow function returns 0 and sets errno to EDOM when x is 0 and y is non-positive, or when x is negative and y is not an integer. In these cases a message indicating DOMAIN error is printed on the standard error output. When the correct value for pow would overflow or underflow, pow returns ±HUGE or 0 respectively, and sets errno to ERANGE.
The sqrt returns 0 and sets errno to EDOM when x is negative. A message indicating DOMAIN error is printed on the standard error output.
These error-handling procedures may be changed with the function matherr(3m).