C's pow function refuses to work with variable exponent

Question

Let\'s say I have the following code snippet:

int i; double value;
for(i = 0; i < CONSTANT; i++) {
  value = (double)pow(2, i);
}

Trying

Answer 1

You need to link with -lm to actually include the math library.

It worked for a hardcoded value because the compiler optimized the pow call away.