is it possible to make forward TYPE declaration

[whatsup]

i have a struct (T1)
inside the struct (T1) i have function pointer which get a struct (T2) pointer as an argument
the problem is that struct T2 doesn't declared yet,
and i get compiler error.

thanks in advanced for any help

[TimoVJL]

something like this:

Code: [Select]

// forward declaration
typedef struct T2 T2;

typedef struct _tagT1 {
T2 *t2;
} T1;


[whatsup]

thank you very much, i'll check this

[whatsup]

I tried this, and it didn't work for me.
what i want to do is:

Code: [Select]

typedef struct _test1 {
  int      num1;
  void   (*PrintNum1)(test1 * );  // <-- this is a pointer to the struct
}test1;

i get the error: Extraneous old-style parameter list.

[TimoVJL]

Code: [Select]

typedef struct _test1 {
  int      num1;
  void   (*PrintNum1)(struct test1 * );  // <-- this is a pointer to the struct
}test1;


[whatsup]

thanks for reply.
this also doesn't work.
here is my code (i mentioned in the first post i'm using a function pointer)

Code: [Select]

typedef struct _test1 {
  void   (*PrintNum1)(struct test1 *);
}test1;


void    test1__PrintNum1 (struct test1 *self);

void    test1__PrintNum1 (struct test1 *self)
{
}

void init(void)
{
 struct test1 t;
 t.PrintNum1 = test1__PrintNum1;
}


[frankie]

In forward reference you have to refer to the tag (_test1) not to the type defined (test1) that must be used in all successive instances:

Code: [Select]

typedef struct _test1 {
  void   (*PrintNum1)(struct _test1 *);
}test1;


void    test1__PrintNum1 (test1 *self);

void    test1__PrintNum1 (test1 *self)
{
}

void init(void)
{
 test1 t;
 t.PrintNum1 = test1__PrintNum1;
}
 

[whatsup]

thank you very much sir.
it works exactly as i wanted.