Thread: Issues with malloc, returning pointer, conflicting types

I'm debugging an assignment due very soon, please help ASAP.


The error is:

Assignment makes pointer from integer without a cast.

So, apparently add_group returns an int, yet the return type is char *


this is the block of code that calls the function which returns a char * pointer:

buffer is delcared as this -------> char *buffer;

Code:

} else if (strcmp(cmd_argv[0], "add_group") == 0 && cmd_argc == 2) {
        buffer = add_group(group_list_addr, cmd_argv[1]);  
        printf("%s", buf);

This is the block of code that is add_group:

Code:

char *add_group(Group **group_list_ptr, const char *group_name) {
    
    
   if (find_group(*group_list_ptr, group_name) == NULL) {
        //malloc space for new group
        Group *newgrp;
        char *groupSucc; 
        char *groupFail;
        if ((groupSucc = malloc(sizeof(group_name) + 21)) == NULL) {
            perror("Error allocating space for add_group success message");
            exit(1);
        strcpy(groupSucc, "Group ");
        strcat(groupSucc, group_name);
        strcat(groupSucc, " added");
        if ((newgrp = malloc(sizeof(Group))) == NULL) {
           perror("Error allocating space for new Group");
           exit(1);
        }
        // set the fields of the new group node
        // first allocate space for the name
        int needed_space = strlen(group_name) + 1;
        if (( newgrp->name = malloc(needed_space)) == NULL) {
           perror("Error allocating space for new Group name");
           exit(1);
        }
        strncpy(newgrp->name, group_name, needed_space);
        newgrp->users = NULL;
        newgrp->xcts = NULL;
        newgrp->next = NULL;
        // Need to insert into the end of the list not the front
        if (*group_list_ptr == NULL) {
          // set new head to this new group -- the list was previously empty
          *group_list_ptr = newgrp;
          return groupSucc;  
        }  else {
        // walk along the list until we find the currently last group 
          Group * current = *group_list_ptr;
          while (current->next != NULL) {
            current = current->next;
          }
          // now current should be the last group 
          current->next = newgrp;
          return groupSucc;
        }
    } else {
            // group EXISTS
            if ((groupFail = malloc(sizeof(group_name) + 21)) == NULL) {
                perror("Error allocating space for add_group failure message");
                exit(1);
            }
            strcpy(groupFail, "Group ");
            strcat(groupFail, group_name);
            strcat(groupFail, " already exists");
            return groupFail;
    }
}

Taking out the * on char *buffer; fixed it

Still not sure whether I am returning what I actually want. The print statement thinks that buffer is an int?!!