Whenever I compile this I get that error, and I am not sure why. I am copying this straight out of a book. Can anyone help?

```
#include <stdio.h>
#include <string.h>

int main(void) {
    char buffer[256];

    printf("Enter your name and press enter:\n");
    fgets(buffer);

    printf("Your name has %d characters and spaces!", strlen(buffer));

    return 0;
}

```