标记字符串时的内存泄漏

Question

I wrote a program in C that tokenizes an input string, and when the user enters "exit", it exits the program.

It tokenizes the string correctly, however, when I test my program with valgrind, I get some memory leaks. The only scenario when I don't get memory leaks is after compiling and then executing, I exit right away.

Here is the output with valgrind: Valgrind Memory Leaks

And here is my code for the program:

    int main() {
       /* Main Function Variables */
       char *buf;
       char *savecpy = NULL;
       char *token;
       size_t num_chars;
       size_t bufsize = 2048;
       int run = 1;
       int tok_count = 0;
       int cmp;

       /* Allocate memory for the input buffer. */
       buf = (char *) malloc(sizeof(char) * bufsize);

       /*main run loop*/
       while(run) {
           /* Print >>> then get the input string */
           printf(">>> ");
           num_chars = getline(&buf, &bufsize, stdin);

           cmp = strcmp(buf, "exit\n");

           if (num_chars > 1) {
               /* Tokenize the input string */
               if (cmp != 0) {
                  /* Display each token */
                  savecpy = strdup(buf);
                  while((token = strtok_r(savecpy, " ", &savecpy))) {
                        printf("T%d: %s\n", tok_count, token);
                        tok_count++;
                    }
               }
               /* If the user entered <exit> then exit the loop */
               else {
                 run = 0;
                 break;
               }
         }
         tok_count = 0;
       }

    /*Free the allocated memory*/
    free(buf);
    return 1; 
}

What may be the problem here that is causing the memory leaks in valgrind? I am freeing my memory for my input string, but I still get memory leaks.

Answer 1

savecpy should be freed. As seen in the manual :

Memory for the new string is obtained with malloc(3), and can be freed with free(3).

savecpy can not be freed after passing through strtok_r third argument, as this function modifies the pointer. Rather pass something like this

char* ptr;
strtok_r(..,.., &ptr);

Then you can free savecpy