Skip to content
  • Home Home Home, current page.
  • Moments Moments Moments, current page.

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
RichFelker's profile
Rich Felker
Rich Felker
Rich Felker
@RichFelker

Tweets

Rich Felker

@RichFelker

Yeah, I do @musllibc, FOSS & infosec stuff. But now is not the time for a mostly-/only-tech Twitter feed.

musl-libc.org
Joined March 2014

Tweets

  • © 2018 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. Rich Felker‏ @RichFelker Sep 18

      ARM Memory Tagging is a great example of why it's A Good Thing that pointer arithmetic and relational operators are only defined for operands within a single array.

      4 replies 6 retweets 20 likes
    2. andrew pikul‏ @misterpikul Sep 18
      Replying to @RichFelker

      Structures? Are we talking about c?

      1 reply 0 retweets 0 likes
      Rich Felker‏ @RichFelker Sep 18
      Replying to @misterpikul

      Yes C. What about structures?

      7:26 PM - 18 Sep 2018
      1 reply 0 retweets 0 likes
        1. New conversation
        2. andrew pikul‏ @misterpikul Sep 18
          Replying to @RichFelker

          I guess pointer arithmetic isn't okay within structures. I guess order isn't guaranteed other. I'm recalling a lot of shaky code from my memory...

          1 reply 0 retweets 0 likes
        3. Rich Felker‏ @RichFelker Sep 18
          Replying to @misterpikul

          All objects in C, including structures, have a /representation/, which is an overaid (permitted to alias) array of unsigned char [sizeof object]. Within this array relational operators and arithmetic are well-defined; otherwise offsetof would make no sense. Order is guaranteed.

          1 reply 0 retweets 1 like
        4. andrew pikul‏ @misterpikul Sep 18
          Replying to @RichFelker

          Order is guaranteed in structures? Even on bit arrays?

          1 reply 0 retweets 0 likes
        5. Rich Felker‏ @RichFelker Sep 18
          Replying to @misterpikul

          Bitfield members don't have addresses or offsets, so it's not really meaningful to ask about their order. Of course bytes corresponding to them appear in the representation though. Within a unit the order is implementation-defined.

          1 reply 0 retweets 0 likes
        6. andrew pikul‏ @misterpikul Sep 18
          Replying to @RichFelker

          Order could be important

          1 reply 0 retweets 0 likes
        7. Rich Felker‏ @RichFelker Sep 18
          Replying to @misterpikul

          Yes. In practice implementations (ABIs) define bitfield bit order to match byte order.

          1 reply 0 retweets 2 likes
        8. Rich Felker‏ @RichFelker Sep 18
          Replying to @RichFelker @misterpikul

          But back to your question, for something like struct { int a, b; } c;, the < operator and other relational operators are not defined for operands &c.a and &c.b (&c.a<&c.b is UB). However (char*)&c.a < (char*)&c.b is defined in the representation array.

          1 reply 0 retweets 0 likes
        9. andrew pikul‏ @misterpikul Sep 18
          Replying to @RichFelker

          If the char* array representation is the only one doesn't one imply the other? I'm assuming there is only one "physical" block of memory defined as the structure.

          1 reply 0 retweets 0 likes
        10. 4 more replies

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2018 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Cookies
        • Ads info