Is it possible the check the function parameter is char array, const string, string pointer to malloc data

I get some problem with the function parameter checking. There are three type of string can be parameter in func(char *str): 1. const string 2. string pointer to a malloc data 3. char 开发者_运维技巧array. It is possible to limit the c function only accept the const string, like "1111"?

I try to write some code like below, but it doesn't work.

struct test{
    const char *val;
};

void func(struct test *t, const char *rodata)
{
    t->val = rodata;
}

But I found I can't check which rodata I pass to func():

/* Test: rodata don't free after function call, it can be the point to*/
func(t, "333");
printf("%s\n", t->val);

/* Test: C function can't check rw char array, even with const ...*/
char rwdata[] = "22222";
func(t, rwdata);
memset(rwdata, '9', sizeof(rwdata));
printf("%s\n", t->val);

/* Test: C function can't check malloc ?*/
char *rwdata2 = strdup("rodata2");
free(rwdata);
func(t, rwdata2); /* cause error */
printf("%s\n", t->val);
}

No -- all three arguments are pointers. There is no way to reliably distinguish between them.

3rd error

you could do this way

typedef struct 
{
   const char* val;

}test;


test func(test t, const char* s)
{
   t.val = s;
   return t;
}


int main()
{
  test t ={0};
  char* p = NULL;

  p= (char*)malloc(4);

  strncpy(p, "abc", 4);


  t = func(t, p);

}