C++ Weekly - Ep 254 - C++23's signed / unsigned size_t Literals

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[Raspredval]

I'am still waiting for static type reflection. Hope it'll make it into the c++23

[ruadeil_zabelin]

I have custom literals in my codebase for exactly this. I called them _size_t and _ssize_t. I'm glad they're going to be a standard.

[LesleyLai]

This will fix one of the most annoying things in my day-to-day C++

[bettkitty]

I missed the "literals" part of the title when i saw the video notification. Now, it makes more sense!

[afborro]

It should have been in c++17 already. What took so long :)

[treyquattro]

confused: size_t is already unsigned, why is there an unsigned qualifier? ptrdiff_t is accepted as the signed counterpart to size_t. The z and t format specifiers are already accepted in printf() since C++11.

I suppose since size_t is implementation-defined, some perverse implementor could decide on a type that allows negative sizes?

[timangus]

Not the same, but related: working with Qt and the standard library in the same project (so basically every Qt project), with any sort of sensible set of warnings enabled your code is covered in static_casts to and from int and size_t :(. (That are no doubt hiding lots of subtle bugs when containers get large.)

[yrtepgold]

What am I missing? Why would someone want to use auto on the lhs and then explicitly name the type on the rhs?

[hkmix]

It seems like given the current revision the EWG accepted z/zu but rejected t/tu, so we're getting one but not the other? Rather curious choice since I think there will definitely be confusion as to why z != ptrdiff_t, even if the paper does justify why that is the case.

[vdvman]

Hello Jason! I am a big fan of C++ Weekly, it has helped me learn so much more about C++ than I had ever hoped to know.
I am just wondering if you ever covered C++20 modules? I can't seem to find a video when searching, and while I have had a look at what cppreference has about modules your videos often go into the small details that are easy to miss and give great examples.

[nivo]

Very useful. Allows using `auto` everywhere like `let` in Rust.

[petermuller]

Great content! However the animations between cuts are a bit wordarty ;)

[praveerroshan]

could you please provide the url of the site which you referred to @31 secs ?

[vorpal]

FINALLY. I am so tired of having to use size_t instead of auto in variable declarations when working with STL collections and manual algorithms.

[pendergastj]

Jason, what's your favorite C++ feature?

[DamianReloaded]

size_t can be kinda evil if one's not careful cross compiling between 32/64 bits. Always storing the result of .size() into a uint64_t is the simplest way to be sure I won't mess up. Also what's wrong with: auto val = (uint64_t)myvec.size(). I only use uint[size]_t s to store integers.

[jbar]

is size_t becoming a language feature then? i.e. a keyword instead of a typedef

[stertingen]

Why is that considered a 'core language feature'? For me it looks like some user-defined literals which can be provided by the STL.

[marco]

What about that all this types are aliases. It gets really nasty if they map to different integer types on different platforms. Like this long long vs long problem. Every time I explain it to novices they ask me way the int32_t is an alias to int not the other way around. Maybe it was a smart idea in the seventies but today it is a bug source. 😏 With modules they should provide a sane integer behavior which you can opt in per file. 😉

[adamshield]

Nice video. What would be the use case of an unsigned size_t do you think?

Edit: oops I meant signed size_t