about typedef void (*FUNCPTR) (void) issues

First, looked at the hard solution code, found that there are similar to the definition of this way:

typedef void (*exec_ref_pic_marking_adaptive_mmco_func) (

GstVaapiDecoderH264 *decoder,

GstVaapiPictureH264 *picture,

Gsth264refpicmarking *ref_pic_marking

);

static const Exec_ref_pic_marking_adaptive_mmco_func mmco_funcs[] = {

Null

Exec_ref_pic_marking_adaptive_mmco_1,

Exec_ref_pic_marking_adaptive_mmco_2,

Exec_ref_pic_marking_adaptive_mmco_3,

Exec_ref_pic_marking_adaptive_mmco_4,

Exec_ref_pic_marking_adaptive_mmco_5,

Exec_ref_pic_marking_adaptive_mmco_6,

};

The use of this method may not be a lot of use, then the following to see how this approach is used:

1 First, the problem relates to the TypeDef void (*FUNCPTR) (void) problem;

To illustrate:

Defines a function pointer type.

For example, the following three functions are available:

void Hello (void) {printf ("Hello!");}

void bye (void) {printf ("Good-bye!") "); }

void ok (void) {printf ("OK! "); }

typdef void (*funcptr) (void);

In this way, a general function is constructed.

You can do this when you use it:

void speak (int id)

{

Funcptr Words[3] = {&hello, &bye, &ok};

Funcptr fun = Words[id];

(*fun) ();

}

If so, speak (0) will show "Hello!" ”

Speak (1) It will show "good-bye!" ”

Speak (2) it will show "OK!" ", from here, you can better understand the beginning of a piece of code, first define a pointer to a function containing three parameters (*decoder,*picture,*ref_pic_marking), and a return type of void, preceded by a typedef, Description Exec_ref_pic_marking_adaptive_mmco_func is an alias of this type, so an array is defined using the alias, and the function of that type is called by the array, respectively.

Second, to give a simple example:

typedef int (*callback) (char *p);

Pointer variable name: CallBack

1.*callback:callback is a pointer

2. (*callback) (): Point to a function

3. (*callback) (char *p): This function has one parameter, type char*

4.int (*callback) (char *p): This function has a return value, type int

Remember, the following semicolon must not forget Oh ~ ~

Summary: Callback is a pointer to a function that has a char* type parameter and returns an int type of data

There is a typedef in front, so now callback is this type of alias.

about typedef void (*FUNCPTR) (void) issues