How to use Strtok for tokenizing a Const char*?

20
votes

I have a const char* variable which may have a value like "OpenStack:OpenStack1". I want to tokenize this const char* using strtok where the delimiter(which is of a const char* type) is ":" . But the problem is strtok is of following type: char * strtok ( char * str, const char * delimiters );

Which means I can't use const char* for the first input as it has to be char*. Could you say me how I can convert this const char* into char*?

Thank you.

3
c++cstrtok
Copy it? linux.die.net/man/3/strdup – James McLaughlin
Did you mean I should copy from that page? – the_naive
No, I meant you should copy the string using the function described. – James McLaughlin
Yup, spot on.I did the same.Thanks – the_naive

3 Answers

23
votes

Since strtok actually writes to your string, you need to make a writable copy of it to tokenize;

char* copy = strdup(myReadonlyString);
...tokenize copy...
free(copy);
2
votes

Declare it as an array:

char tokenedStr[] = "OpenStack:OpenStack1";

if not possible, copy it to a char array.

0
votes

You can make a copy of your non-modifiable string and then use strtok.

You can portably use malloc and strcpy to copy the string.