Why does the following C program give a bus error?

Question

I think it's the very first strtok call that's failing. It's been a while since I've written C and I'm at a loss. Thanks very much.

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

int main(int argc, char **argv) {
  char *str = "one|two|three";

  char *tok = strtok(str, "|");

  while (tok != NULL) {
    printf("%s\n", tok);
    tok = strtok(NULL, "|");
  }

  return 0;
}

Answer 1

String literals should be assigned to a const char*, as modifying them is undefined behaviour. I'm pretty sure that strtok modifies it's argument, which would explain the bad things that you see.

Answer 2

There are 2 problems:

1. Make str of type char[]. GCC gives the warning foo.cpp:5: warning: deprecated conversion from string constant to ‘char*’ which indicates this is a problematic line.

2. Your second strtok() call should have NULL as its first argument. See the docs.

The resulting working code is:

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

int main(int argc, char **argv) {
  char str[] = "one|two|three";

  char *tok = strtok(str, "|");

  while (tok != NULL) {
    printf("%s\n", tok);
    tok = strtok(NULL, "|");
  }

  return 0;
}

which outputs

one
two
three