I can try. But I'm a little rusty.

And someone "borrowed" my copy of the new testament and didn't give it back. Grrrr.

In my main I have a pointer to a struct that has elements h and w

deus vult @dmckee

There, I can access these elements like

int foo = IST_logo->h;

IST_logo is the struct

Now, I have a function that takes SDL_Surface **_logo

How do I reference the element inside the function?

i wanted to make a religious joke about that but figured i'd just not say it

Something like (*_logo)->h ought to do it, I think. Hard to be certain without looking at more of the code.

Ha

It's the parenthesis that were missing

interesting

And I feel compelled to complain that you shouldn't be using _ prefixes. They are reserved.

I know, I will refactor the naming

I just need to bootstrap this

Thanks @dmckee!

bootstrap?

Lots of the precedence relationships for c's operators are weird enough that parentheses spring up in odd places.

@BalarkaSen In this instance "the new testament" is the 2nd edition of The C Programing Language by K&R.

@0celouvsky "Just make it work"

Though someone needs to write an equivalently short and dense book for a newer version than c90. Alas Ritchie is gone.

Yeah, Ritchie is gone :(

I'm glad Knuth is still around

why?

He's a Computer Scientist's Computer Scientist

he's going to release another edition of his books

and they're gonna be more expensive than ever

@BernardoMeurer What does that even mean?

Yeah, he's nuts, he says he's going to volume 10

He's currently at 4

@0celouvsky Not sure, someone once said that about Grothendiek and I thought it sounded cool

he was a nut

lots of these guys are bonkers

Perelman...

which guys

> Although in applications we deal with analytic manifolds as a rule

wat

I've never once seen an analytic manifold used unironically

Lie groups don't count

$\Bbb R^n$ is analytic

Hm

I think the guy who told me that maybe we could have contractible curves covered by simply connected charts if they were injective was wrong

Or... was he

I'm not sure

the example in mind is fairly convoluted

No I think he might be right

@Slereah there are plenty analytic manifolds

But one never uses them as analytic manifolds

wait what

The new coordinates don't include the old coordinates

Oh, I think those are just arrival times

nvm

I'll have to work out the coordinates myself

@dmckee Still here?

I like when a book talks about things I already know

I can nod violently while reading

Hm

@BernardoMeurer Well, I'm back.

If we have two spacetimes $g^1_{\mu\nu} = \eta_{\mu\nu} + k^1_{\mu\nu}$ and $g^2_{\mu\nu} = \eta_{\mu\nu} + k^2_{\mu\nu}$

Is $g_{\mu\nu} = \eta_{\mu\nu} + k^1_{\mu\nu}+ k^2_{\mu\nu}$ a spacetime, assuming that $k^1$ and $k^2$ have disjoint support

@dmckee How can I calloc a 2D array so that I can access it like foo[a][b]?

Pretty sure it's correct

Uh...

Yeah :P

Try something like int *(foo[a]) = calloc(b,sizeof(int[a]));

Maybe.

Formally, of course it is a pointer, but you can still access it with array semantics.

@dmckee If I try that everything is red, lol

But I have to warn you, that code using this kind of trickery is a pain to work with unless you can isolate all the clever bits.

"Compound array initializer is expected"

@BernardoMeurer I take that is you IDE tell you it is systactically incorrect?

Yes

/home/meurer/src/prog/project01/main.c:75:5: error: variable-sized object may not be initialized
     int *(board[game_sz]) = calloc(game_sz, sizeof(int[game_sz]));
     ^~~

GCC doesn't like it either

Then I'm stumped without getting a book and really poring over it.

I miss my K&R.

Hmmm

Let me try some pointer magic

Y U abuse compiler?

^^ words that almost always presage disaster.

int **board = (int **)(calloc((size_t)(game_sz), sizeof(int *)));
for(int i = 0; i<game_sz; ++i) board[i] = (int *)calloc((size_t)(game_sz), sizeof(int));
board[0][0] = 1;

Works

@DanielSank Abuse? How?

@DanielSank Oh, I didn't go for the magic :P

@BernardoMeurer makes sense, because to do multilevel indexing in C you need to have an array of pointers

I went for the verbose way

@DavidZ Yep :)

When I've had to do this I made a macro INDEX_2D(n, i, j) = j * n + i or something like that, then I could just do board[INDEX_2D(n, 0, 0)] = 1 and the like

I didn't want to bother with the complexity of arrays of pointers

@DavidZ Yeah I'm trying to steer away from macros

I think this pointer to pointer approach is nice enough

Sure, whatever works for you

I suppose you can get away with malloc-ing the first array because you're initializing all the elements right afterward anyway

This is already me refactoring my refactor to make it less refartorant so that the prof accepts my code

@DavidZ calloc is faster than malloc on linux :P

really? weird

@BernardoMeurer why?

Yep, for really interesting reasons, I have an article, one second

@DanielSank Because the kernel cheats

@BernardoMeurer Did you see what I was saying "why" to?

@DanielSank Nope :P

Because I dislike macros

@BernardoMeurer o_O

I think they look ugly and are generally not needed

@BernardoMeurer Ho boy. Ok, try to write a nice RPC system.

I will using solely GOTO

and booleans

You'll get rekt.

@0celouvsky change your username to ILoveMeasureTheory.

@BernardoMeurer oh, that's different. malloc + memset will of course be slower than calloc. But you're not using memset or any equivalent, so that's not relevant for your code snippet.

@DavidZ My bad, I need everything to be 0-initialized

I also generally dislike malloc

I think it makes it easy to screw up and access unitialized memory

I'm just saying you don't need board to be zeroed in this case, not unless you're doing some multithreading nonsense or the like. Not that it really makes a huge difference.

Stop generally disliking stuff. Different stuffs are good for different things, and stuff.

@DavidZ Hm? I'm telling you I NEED it zeroed for my use case :P

@DanielSank I dislike GOTO

@BernardoMeurer Ever used one?

@G.Bergeron Every week

@BernardoMeurer why?

@G.Bergeron Coding in assembly for my MIPS CPU, Writing C code but the implementation of libc is incomplete (I'm writing my own kernel).

@BernardoMeurer In what physics coursework were you asked to do that o_0 ?

@G.Bergeron None.

None

Computer engineering courses.

@BernardoMeurer I beat you.

MIPS part for Computer Architecture

kernel part is to satisfy my masochistic tendencies

dafuq is MIPS?

Million Instructions Per Second?

An ISA

It's too low-level for me... I like reading about it, understanding it and using what others did!

Not very good one, but easy to make

Something about no interlocked pipeline

in the cpu

I'm the kind of Computer Limbo

@BernardoMeurer what do you mean?

I always go to the lowest level :P

@BernardoMeurer Me too! ... in theory.

@BernardoMeurer So when do you plan on refining silicon and doing lithography? :p

@G.Bergeron In a couple years :P

@BernardoMeurer False. I'm working with capacitors and circuit traces, boi.

rekt

I'm starting to work on rebuilding SH in a Spartan 6 right now

@DanielSank Yes, you also cannot compute anything that requires more than 15 bits

shaddap!

REKD

(I have never been rekt harder than that. Ever)

<3

That was meant as an incentive

Now you work not just for money and recognition, but for your honor to unrek yourself

@BernardoMeurer Hmm... that depends on how you count!

In a a way, you are on the digital level of abstraction and he is on the analog level (possibly). Hence, there are so much more degrees of freedom interacting with an analog computing power blasting away anything you're doing :p

@G.Bergeron I'll accept that when his computer runs Doom

Cause even my calculator does

@BernardoMeurer Bwah, your rigging the test in your favour

Am not! Running doom is a test standardized by the ISO

and recognized internationally