Thread: Confused about warning: return from incompatable pointer type

I am a bit confused as to why I am getting the warning "return from incompatable pointer type" with the code I have written below. I define yelp as a YelpDataBst* and the function has a return type of YelpDataBst*, so why am I getting this warning?

Code:

typedef struct BusList_t{
   long int addressOffset;
   long int reviewOffset;
   struct BusList_t* next;
}BusList;


typedef struct BusTree_t{
  char* name;
  //int id;
  BusList* locations;
  struct BusTree_t* left;
  struct BusTree_t* right;
}BusTree;

struct YelpDataBst{
  BusTree* Bushead;
};

struct YelpDataBST* create_business_bst(const char* businesses_path, const char* reviews_path){
  
  if(fopen(businesses_path,"r") == NULL || fopen(reviews_path,"r") == NULL)
    return NULL;
  FILE* fp_bp = fopen(businesses_path, "r");
  FILE* fp_rp = fopen(reviews_path, "r");
  struct YelpDataBst* yelp = malloc(sizeof(struct YelpDataBst));
  
  int ID = -1;
  int tempID;
  long int addressOffset;
  long int reviewOffset;
  char line[2000];
  char line2[2000];
  char* token;
  char* token2;
  char* name;
  int len;
  
  BusList* busListHead = NULL;
  BusTree* busTreeNode = NULL;
  BusTree* busTreeHead = NULL;

   ID = -1;
   tempID = 0;
   fgets(line,2000,fp_rp);
   fgets(line2,2000,fp_bp);
   fseek(fp_rp,0, SEEK_SET);
   fseek(fp_bp,0,SEEK_SET);
   int ct = 0;
   while(!feof(fp_rp)){
     
     len = strlen(line);
     token = strtok(line, "\t");
     tempID = atoi(token);
     if(ct == 0){
       tempID = 1;
       ct++;
     }
     if((ID != tempID || (ID < 0)) && tempID != 0){
    token2 = strtok(line2, "\t");
    addressOffset = ftell(fp_bp);
       if(tempID == 1)
      tempID = 0;
    token2 = strtok(NULL, "\t");
    if(token2 != NULL){
      if(name != NULL)
        if(strcmp(token2, name) == 0){
          fgets(line2, 2000,fp_bp);
          token2 = strtok(line2, "\t");
          token2 = strtok(NULL, "\t");
        }
      name = strdup(token2);
    }
    reviewOffset = ftell(fp_rp);
    if(tempID != 0)
      reviewOffset -= len;
    ID = atoi(token);
    busTreeNode = BusTree_create(name, busListHead, addressOffset, reviewOffset);
    busTreeHead = BusTree_insert(busTreeHead, busTreeNode); //replace with create node for tree
    free(name);
    fgets(line2,2000,fp_bp);
      }
      fgets(line,2000,fp_rp);
      
}    
  yelp->Bushead = busTreeHead;
  BusTree_print(yelp->Bushead);
  BusTree_destroy(busTreeHead);
  return yelp;
  
}

Originally Posted by Purdue

...and the function has a return type of YelpDataBst*

Umm...no it doesn't:

Code:

struct YelpDataBST* create_business_bst(const char* businesses_path, const char* reviews_path){

C is case sensitive

Oh gosh...I can't believe I didn't see that Thank you very much for pointing that out to me

Originally Posted by Salem

Code:

  if(fopen(businesses_path,"r") == NULL || fopen(reviews_path,"r") == NULL)
    return NULL;
  FILE* fp_bp = fopen(businesses_path, "r");
  FILE* fp_rp = fopen(reviews_path, "r");

This leaks file handles.
Open them once, then test for NULL.

Code:

if ( (fp_bp = fopen(businesses_path, "r")) == NULL || (fp_rp = fopen(reviews_path, "r")) == NULL )
{
    return NULL;
}
else
..

Originally Posted by Al3

Code:

if ( (fp_bp = fopen(businesses_path, "r")) == NULL || (fp_rp = fopen(reviews_path, "r")) == NULL )
{
    return NULL;
}
else
..

On my arch, FILE* and int are in the same size. You can do this too:

Code:

switch((int)fp)
{
    case NULL : return NULL;
    break;
    default :
    // ...
}

Originally Posted by phantomotap

O_o

The use of `fclose(0)' relies on undefined behavior.

[Edit]
That issue may have been resolved in C11 standard.
[/Edit]

You should normalize this with `myfclose' or similar.

Soma

Hey pony, I call undefined behavior when someone, potentially suspicious ask a weird question.
On the other hand..

I've seen people to separate code with semicolons.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Code that makes sense:

Code:

int main(void) { return (0+1)-1; }

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
Race who will crash the exe with less code as
possible. The winner's code:

Code:

int main(void) { main(); }

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
The worst attempt of C reinvention:

Code:

#define ULTIMATE_TERMINATOR(sexy) return sexy; }
int main(void)
{
    // do something as equally remarkable
    // ..
    ULTIMATE_TERMINATOR(0)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

Code:

#define NOTHING int main(void) { }

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
The most inoculate question:
hiall im new 2 prograing and i need help
can u help me or not if not i go
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
And on top of that "Windows" had to blow out with
the following error when adjusting partition size:
*Invalid Parameter*
...I mean what.. what is that even supposed to mean