A portable way to untie a typedef pointer?

Question

This, unfortunately, is defined in some external library: cannot touch!

// library.h
typedef struct {
    long foo;
    char *bar;
   /* ... (long & complex stuff omitted) */
} *pointer_to_complex_struct_t;

Now Question : how to declare a variable ? complex_struct_t

• Ideal solution, but not allowed! (cannot change external library):

  // library.h
    /* ... (long & complex stuff omitted) */
  } complex_struct_t, *pointer_to_complex_struct_t;
  
  
  // my.h
  extern complex_struct_t my_variable;
  

• Intolerable Solution (gcc):

  // my.h
  extern typeof( * (type_placeholder)0 )  my_variable; // Thanks caf!
  

• Other? It's better? Thank!

Bonus question: The same question for a function pointer (if there is any difference, I doubt it).

---

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///// library.h //////
// Signature has been simplified
typedef double (*ptr_to_callback_t)(long, int, char *);
// Too bad this is not provided: typedef double callback_t(long, int, char *);

///// my.h /////
// This avoids copy-paste but is not portable
typedef typeof( * (ptr_to_callback_t)0 ) callback_t;

extern callback_t callback_1;
extern callback_t callback_2;
extern callback_t callback_3;
// etc.

---

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Answer 1

, , C. ++ .

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typedef struct {
 ///same  struct
} complex_struct_t;

, &complex_struct_t pointer_to_complex_struct_t, unnamed struct {//your members}; reinterpret_casting, ...

Answer 2

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typedef struct {...} *ptr_to_struct;

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ptr_to_struct s = malloc(sizeof *s);

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typedef struct {...} *ptr_to_struct;
ptr_to_struct foo() {...}

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Answer 3

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Answer 4

:

pointer_to_complex_struct_t newStruct ( void ) {
    pointer_to_complex_struct_t ptr = 
         (pointer_to_complex_struct_t) malloc ( sizeof (*pointer_to_complex_struct_t) );
    return ptr;
}

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char data[0];

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