C – TypedEf how to function pointer

typedef void (print)(void);
void do_something ( void) {printf("Hello World\n"); }

print *pr;
pr = &do_something;
pr(); // Hello World

typedef void (print)(void);
void do_something (void) {printf("Hello World\n") ; }

print *pr;
pr = do_something;
pr(); // Hello World

typedef void (print)(void);
void do_something ( void) {printf("Hello World\n"); }

print pr;
pr = do_something; // compile error
pr = &do_something; // compile error< br />pr();

#include 
typedef void print(void);
static void dosomething(void) {printf("Hello World\n"); }

int main(void)
{
 print *f1 = dosomething;
 print *f2 = &dosomething;
 f2();
 (f1)(); 
 (*f1)();
 (**f2)();
 (***f1)();
 (****f2)(); 
 (*****f1)();
}

gcc- O3 -g -Wall -Wextra -Werror -Wmissing-prototypes -Wstrict-prototypes \
 -Wold-style-definition -std=c99 xx.c -o xx

I think I may suffer from the terrible “accidental programmer” disease, at least when it comes to typedefs and function pointers Time. So I have been experimenting with various combinations involving these, according to what I got

However, when I continue to try different combinations instead of analyzing the results, I am now just lost in the process.

I hope you Can help me figure out this mess.

First code example

typedef void (print)(void);
void do_something ( void) {printf("Hello World\n"); }

print *pr;
pr = &do_something;
pr(); // Hello World

Second code example

typedef void (print)(void);
void do_something (void) {printf("Hello World\n") ; }

print *pr;
pr = do_something;
pr(); // Hello World

How does the code example above work, as if ‘&’ has no effect on function names

The third code example

typedef void (print)(void);
void do_something ( void) {printf("Hello World\n"); }

print pr;
pr = do_something; // compile error
pr = &do_something; // compile error< br />pr();

I hope one of the tasks above will work here, but damn it! I really don’t understand function pointers (maybe typedef).

The address of the function name and the ordinary function name are the same, so & is for the function name No effect.

Similarly, when using function pointers, multiple dereferences are not a problem:

#include < br />typedef void print(void);
static void dosomething(void) {printf("Hello World\n"); }

int main(void)
{ 
 print *f1 = dosomething;
 print *f2 = &dosomething;
 f2();
 (f1)();
 (*f1)();< br /> (**f2)();
 (***f1)();
 (****f2)();
 (*****f1) ();
}

Compile fully under the following conditions:

gcc -O3 -g -Wall -Wextra -Werror -Wmissing- prototypes -Wstrict-prototypes \
 -Wold-style-definition -std=c99 xx.c -o xx

I will not say that multiple stars are good style; it is not. It is ‘Weird, (yes, you might say) abnormal’. One is enough (a star is mainly for people like me, who learned to use C programming before the standard said “You can call a function through a pointer without using (* pointer_to_function) (arg1, arg2) notation; if you like “), you can write pointer_to_function(arg1, arg2). Yes, this is strange. No, no other types (or categories) exhibit the same behavior, thank God .