Passing pointer argument by reference under C?

Question

#include 
#include 

void
getstr(char *&retstr)
{
 char *tmp = (char *)malloc(25);
 strcpy(tmp, \"hello,world\");
 retstr = tmp;
}         


        

Answer 1

There is an interesting trick in libgmp which emulates references: typedef mpz_t __mpz_struct[1];

and then you can write like this:

mpz_t n;
mpz_init(n);
...
mpz_clear(n);

I would not recommend to use this method, because it may be incomprehensible for others, it still does not protect from being a NULL: mpz_init((void *)NULL), and it is as much verbose as its pointer-to-pointer counterpart.