Woe unto any user that doesn't know that "pow" is a standard library function in C. The C standard allows this inconsistent behavior, sadly (Section 7.1.3 of N1124). I think C++ is better, at least based on how GCC behaves.

pow_wtf.c

#include <stdio.h>

double pow(double x, double y)
{
    return x + y;
}

int main()
{
    volatile int y = 1;
    printf("%f\n", pow(10, y));  // prints 11.000000
    printf("%f\n", pow(10, 1));  // prints 10.000000
    return 0;
}