Question

I am using strtok() the string tokenizer

input is like say

"a,b,c,d|12,34,56,78"

I am doing

      char * cols;
      char * vals;
      $char col_val_temp[1024] = {0};
      $char col_val[1024] = {0};

      cols = strtok(input,"|");
      vals = strtok('\0',"|");
      // now vals will have "12,34,56,78"
      strcpy(col_val_temp,vals);
      strcpy(col_val,col_val_temp);

and in the later part of code I am again using strtok on vals but, I see in debugger that suddenly out of no where the value of col_val becomes null while there is data present in col_val_temp. I have not done any operation on col_val string, so I don’t understand why the data in there is getting lost.

Can someone please explain why I am getting this behavior and how to overcome this.
I am stuck because of this.

Thanks !!!

Answer 1

There is (at least) one buffer overrun problem in your code.

You do a strcpy to seqno. seqno is declared only one character long, so the string terminator will probably overwrite the pointer value of cols.