Thread: domain split function

I am new on C

Please guide me how to fix the problem "Segmentation fault"

Thank you

Code:

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

#define BUF_SIZE 1024

char *domainsplit(char *fdomain) {
   int strlen_buf;
   int i;
   int dot;
   char *domain;
   
   unsigned char tmp_buf[BUF_SIZE];
   
   strlen_buf = strlen(fdomain);
   
   tmp_buf[strlen_buf] = '\0';
   strcpy(tmp_buf, fdomain);  
   
   for (i = 0; i < strlen_buf; i++) {
          tmp_buf[i] = tolower(tmp_buf[i]);
   }
    
   dot = 0;
   
   for (i = strlen_buf - 1; i >= 0; i--)
          if ((tmp_buf[i] == '.') &&
              ((dot > 0) ||
               ((strlen_buf - i) > 3)) &&
              (++dot >= 2))
            break;
                        
   sprintf(domain,"%s", (dot >= 2) ? (tmp_buf + i + 1) : tmp_buf);
   return domain;
}
 
int main(void) {
  char *txt;
  txt = domainsplit("43476347.www.blahblah.com"); 
  // show return  blahblah.com
  printf("%s",txt);  
  return(0);
}

How about allocating some memory for your domain variable before you try to use it?

Originally Posted by rags_to_riches

How about allocating some memory for your domain variable before you try to use it?

if I change from

Code:

char *domain;

to

Code:

char *domain[BUF_SIZE];

It has warning messages.

Code:

domainsplit_func.c:35: warning: passing arg 1 of `sprintf' from incompatible pointer type
domainsplit_func.c:36: warning: return from incompatible pointer type
domainsplit_func.c:36: warning: function returns address of local variable

That now becomes an array of pointers to char. How about using malloc?