How does initial allocation work for the stack example?

[pmcjones]

The stack example on https://github.com/c3lang/c3c includes code to realloc the stack when size catches up with capacity, but I don't see how the initial allocation (and initialization of the size and capacity variables) takes place.

[lerno]

C3 uses zero initialization by default, so we'll always get it with zero size and capacity. Realloc can safely be used for the first allocation because if you pass null to realloc it essentially works as malloc.

[pmcjones]

How does doubling capacity of zero ever get to a nonzero capacity? Has anyone tried running this code?

[lerno]

Look at the if statement

this.capacity *= 2;
if (this.capacity < 16) this.capacity = 16;

In the case this.capacity = 0, then it sets the new capacity to 16. So that works.

And yes, it's working and running.

[pmcjones]

Thank you; obviously I wasn't studying the code carefully. I'd be tempted to replace that with:

if (this.capacity == 0) this.capacity = 16;
else  this.capacity *= 2;

and maybe add a comment about zero initialization as a heads-up for C programmers.

[lerno]

I tried to mention default zero init several times in the docs. Do you have a suggestion where to add it in the docs in order to catch the attention of more C programmers?

[pmcjones]

I found the discussion of initialization quickly when I went to https://c3-lang.org/getting-started/ and looked under Language Fundamentals / Variables, so that is good. I meant to suggest that you add a comment such as:

usz capacity; // zero-initialized by default

to the stack example on https://github.com/c3lang/c3c, since that is the very first exposure some people (like me) will have to the language.

Another topic: I'm an old fogey (first programming job in 1967), and I'm used to there being a language reference manual in addition to other types of documentation such as tutorials, quick-start guides, etc. I find your documentation tends to have all the facts, but not always where I'd expect to find them. For example, Language Fundamentals / Statements mentions if statements from time to time, but the first example doesn't have an else clause. It sounds like I should interpret the sentence "Statements largely work like in C, but with some additions." as meaning: it's just like C unless we say something different somewhere in these web pages." The nice thing about a reference manual is that it puts a bound on where someone needs to look to get an answer to a question about a language, and it will often have an index to make that even easier.