I'm a huge fan of the 'parse, don't validate' idiom, but it feels like a bit of a hurdle to use it in C - in order to really encapsulate and avoid errors, you'd need to use opaque pointers to hidden types, which requires the use of malloc (or an object pool per-type or some other scaffolding, that would get quite repetitive after a while, but I digress).

You basically have to trade performance for correctness, whereas in a language like C++, that's the whole purpose of the constructor, which works for all kinds of memory: auto, static, dynamic, whatever.

In C, to initialize a struct without dynamic memory, you could always do the following:

    struct Name {
        const char *name;
    };

    int parse_name(const char *name, struct Name *ret) {
        if(name) {
            ret->name = name;
            return 1;
        } else {
            return 0;
        }
    }

    //in user code, *hopefully*...
    struct Name myname;
    parse_name("mothfuzz", &myname);

But then anyone could just instantiate an invalid Name without calling the parse_name function and pass it around wherever. This is very close to 'validation' type behaviour. So to get real 'parsing' behaviour, dynamic memory is required, which is off-limits for many of the kinds of projects one would use C for in the first place.

I'm very curious as to how the author resolves this, given that they say they don't use dynamic memory often. Maybe there's something I missed while reading.