How to use strtok to parse string at whitespace?

Question

I am trying to use strtok() to parse a string deliminated by spaces. From what I can tell, I am using it correctly, but it won't run on ideone.com. Is there anything wrong with the following code? I just get Runtime error time: 0 memory: 2288 signal:11

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

static void test(char *command)
{
    char* output = strtok(command, " ");
    printf("%s\n", output);
}

int main(void) {

    test("set_rate 200");

    return 0;
}

Here it is on ideone.com if you want to try it.

Answer 1

Always consult the man pages first.

strtok(3) says:

Be cautious when using these functions. If you do use them, note that:

• These functions modify their first argument.

• These functions cannot be used on constant strings.

Answer 2

strtok will modify the string passed as the first parameter, so you can't pass a string literal, change your main like this:

int main(void) {  
    char str[] = "set_rate 200";
    test(str);
    return 0;
}

str here is an char array, but not a string literal.