Pointer to struct "undeclared (first use in this function)"

Question

I'm trying to implement a linked list in C, and i'm having a hard time figuring out why I'm getting the following error when compiling:

entryList.c:7:11: error: 'tmp' undeclared (first use in this function)
   entry * tmp = NULL;
entryList.c:7:11: note: each undeclared identifier is reported only once for
   each function it appears in
       ^

I already wrote a few linked lists for this program, they all use a similar syntax, but the compiler only complains about this one.

I have my struct definition in header.h:

/*definition of entry type*/
typedef struct entry
{
  char * label;
  short int address;
  struct entry * next;
} entry;

and in entryList.c, I'm writing a function to add a node to the linked list.

#include "header.h"

static entry * head = NULL;

void addEntry(char * entry, int line)
{
  entry * tmp = NULL;
  char * label = NULL;
  tmp = malloc(sizeof(entry));
  label = malloc(sizeof(char)*MAX_LINE);
  strcpy(tmp->label, entry);
  tmp->address = 0;
  tmp->next = NULL;

  if (!head)
  {
    head = tmp;
  }
  else
  {
    entry * p = head;
    while (p->next)
      p = p->next;
    p->next = tmp;
  }
}

Answer 1

void addEntry(char * entry, int line)
{
    entry * tmp = NULL;

You have both a parameter and a type named entry. Change one of them to something else.