Struct declaration in C -

i have simple program in pure c, reading records file , putting linked list. not allowed use global variables. program looks this:

here includes #defines  function headers list manipulation:  void add_item(record * p, ll * ll);  void print_all(ll * ll);  void load(ll * ll);  ...      int main(int argc, char const *argv[])     {          // sample struct defining 1 record         typedef struct record         {             char sign[10];             long int isbn;             char name[100];             char authors[100];             long int date;             int id;             struct record * next;         } record;          // information linked list (ll)         typedef struct ll         {             record * head;         }ll;          // create new linked list         ll * ll = (ll *) malloc(sizeof(ll));          // init          ll->head = null;          // other work ll, record ... }  // functions self  // add item p ll void add_item(record * p, ll * ll) {     if (ll->head == null)     {         ll->head = p;         ll->head->next = null;     }     else     {         record * cur = ll->head;          while(cur->next != null)             cur = cur->next;         cur->next = p;     } }  void print_all(ll * ll) {     if (!ll->head)     {         printf("%s\n", "ll->head null...");         return;     }      record * cur = ll->head;      while(cur)     {         printf("%s\n", cur->name );         cur = cur->next;     } }  // other functions 

now when compile gcc on ubuntu 12.04 get:

project.c:20:15: error: unknown type name ‘record’ project.c:20:27: error: unknown type name ‘ll’ project.c:21:16: error: unknown type name ‘ll’ project.c:22:11: error: unknown type name ‘ll’ project.c:145:15: error: unknown type name ‘record’ project.c:145:27: error: unknown type name ‘ll’ project.c:162:16: error: unknown type name ‘ll’ project.c:182:11: error: unknown type name ‘ll’ 

how can let compiler know of struct record , struct ll before function headers, when structs self , declared in main()?

you can't.

the declarations must visible same level functions declared in.

move struct declarations before list function prototypes.

or add pre-declaration:

typedef struct record record; 

as long list functions dealing pointers (record *), should work.