Is there a nicer way to do c named arguments?

Question

I'm trying to implement a flexible debug macro/function lib and named/optional arguments seem like the best way to implement the functions.

Is there a nicer way to do named arguments in c then the following?

enum named_args {NAME,ADRESS,AGE,NA_SENTINEL};

void named_arg_initializers(struct person p, enum * named_args)
{
    enum named_args * current_name;
    enum named_args * current_arg;
    ...
    if(named_args==NULL)
        return;
    current_name = named_args[0];
    current_arg = named_args[1];
    while(current_name!=NA_SENTINEL)
    {
        current_name+=2;
        current_arg+=2;
        if(current_name==NAME)
            p.name=current_arg;
        else if(...
        ...
        }
        ...
    }
    ...
}

Answer 1

Sure.

struct toto {
  unsigned age;
  char name[25];
};

void func(struct toto);

...

func((struct toto){ .name = "you", .age = 18 });

or if you want you may wrap that in a macro

#define FUNC(...) func((struct toto){ __VA_ARGS__ })
...
FUNC(.name = "you", .age = 18 );

Answer 2

The way you've shown isn't valid unless the named arguments are all compatible with enum (you could fix that by using a void * argument).

However, you could do something similar with varargs which looks neater:

#include <stdarg.h>

enum named_args { NAME, ADDRESS, AGE, NA_SENTINEL };

void named_arg_initializers(struct person *p, ...)
{
    va_list ap;
    enum named_args argn;

    va_start(ap, p);
    for (argn = va_arg(ap, enum named_args); argn != NA_SENTINEL; argn = va_arg(ap, enum named_args))
    {
        switch (argn)
        {
          case NAME:
            p->name = va_arg(ap, char *);
            break;

          case AGE:
            p->age = va_arg(ap, int);
            break;

          /* ...  */
         }
    }
    va_end(ap);

    /* ... */
}

You'd use it like so:

named_arg_initializers(&p, AGE, 110, NAME, "Claude Choules", NA_SENTINEL);