int8_t/uint8_t

Collapse
This topic is closed.
X
X
Collapse
 
  • Page of 1
  • Time
  • Show
Clear All
new posts
Previous template Next
  • Chris Forone
    #1

    int8_t/uint8_t

    hello group,

    is the cast of int8_t and uint8_t in char for streaming in both
    directions (put(), get()) defined/plattform independent?

    i have read here in the forum, that int8_t and uint8_t are guaranteed 2s
    complement, ist the cast between them bit-identical (or is to big
    unsigned in signed undef)?

    are all three chars (char, signed char, unsigned char) on every
    plattform the same size?

    is there a best practise to stream char plattform independend?

    thanks a lot!

    cheers, chris
    Tags: int8_t, uint8_t*
    • joseph cook
      #2
      Re: int8_t/uint8_t

      On Jul 3, 2:30 am, Chris Forone <4...@gmx.atwro te:
      hello group,
      >
      is the cast of int8_t and uint8_t in char for streaming in both
      directions (put(), get()) defined/plattform independent?
      >
      i have read here in the forum, that int8_t and uint8_t are guaranteed 2s
      complement, ist the cast between them bit-identical (or is to big
      unsigned in signed undef)?
      >
      are all three chars (char, signed char, unsigned char) on every
      plattform the same size?
      >
      is there a best practise to stream char plattform independend?
      >
      thanks a lot!
      >
      cheers, chris
      I'm not sure I understand your question; but I think the quick answer
      is 'no'; at the very least you must consider endianess issues.

        Comment

        • Fred Zwarts
          #3
          Re: int8_t/uint8_t

          "Chris Forone" <4one@gmx.atwro te in message news:g4hrm1$dsl $1@newsreader2. utanet.at...
          hello group,

          is the cast of int8_t and uint8_t in char for streaming in both
          directions (put(), get()) defined/plattform independent?
          I don't think int8_t and uint8_t are defined on all platforms.
          i have read here in the forum, that int8_t and uint8_t are guaranteed 2s
          complement, ist the cast between them bit-identical (or is to big
          unsigned in signed undef)?
          Probably.
          are all three chars (char, signed char, unsigned char) on every
          plattform the same size?
          On all platforms sizeof (char) == sizeof (signed char) == sizeof (unsigned char) == 1.
          is there a best practise to stream char plattform independend?
          I don't understand this question, but probably there is a best practice.

            Comment

            • Chris Forone
              #4
              Re: int8_t/uint8_t

              joseph cook schrieb:
              On Jul 3, 2:30 am, Chris Forone <4...@gmx.atwro te:
              >hello group,
              >>
              >is the cast of int8_t and uint8_t in char for streaming in both
              >directions (put(), get()) defined/plattform independent?
              >>
              >i have read here in the forum, that int8_t and uint8_t are guaranteed 2s
              >complement, ist the cast between them bit-identical (or is to big
              >unsigned in signed undef)?
              >>
              >are all three chars (char, signed char, unsigned char) on every
              >plattform the same size?
              >>
              >is there a best practise to stream char plattform independend?
              >>
              >thanks a lot!
              >>
              >cheers, chris
              >
              I'm not sure I understand your question; but I think the quick answer
              is 'no'; at the very least you must consider endianess issues.
              i only use (u)int8_t/(u)int16_t/(u)int32_t in my app. the endianess is
              no problem, because i can only stream char, which is signed/unsigned
              char (depends on impl.). the 16 bit i stream with Put(val >8) and
              Put(val), the 32 bit with Put(val >24) ... Put(val), the Gets() are
              equivalent. i think, serialized objects should be readable on most
              plattforms, i only need the big 3 (linux/mac/win, alphabetical). the
              only problem is, that i have to cast before the shift to unsigned char,
              so the bit-identical is very important because i can only test on 2
              plattforms...

              cheers, chris

                Comment

                • Bo Persson
                  #5
                  Re: int8_t/uint8_t

                  Chris Forone wrote:
                  hello group,
                  >
                  is the cast of int8_t and uint8_t in char for streaming in both
                  directions (put(), get()) defined/plattform independent?
                  >
                  i have read here in the forum, that int8_t and uint8_t are
                  guaranteed 2s complement, ist the cast between them bit-identical
                  (or is to big unsigned in signed undef)?
                  They are twos complement, *if they exist*. On platforms with ones
                  complement, or 9 bit bytes, you're toast.
                  >
                  are all three chars (char, signed char, unsigned char) on every
                  plattform the same size?
                  They are all the same size on a given platform. Was that your
                  question?
                  >
                  is there a best practise to stream char plattform independend?
                  The best way to be platform independent is to define the transport
                  format separately. They you have to implement this on each platform,
                  in a platform dependent way.


                  Bo Persson


                    Comment

                    • Greg Herlihy
                      #6
                      Re: int8_t/uint8_t

                      On Jul 3, 4:21 am, joseph cook <joec...@gmail. comwrote:
                      On Jul 3, 2:30 am, Chris Forone <4...@gmx.atwro te:
                      is the cast of int8_t and uint8_t in char for streaming in both
                      directions (put(), get()) defined/plattform independent?
                      >
                      i have read here in the forum, that int8_t and uint8_t are guaranteed 2s
                      complement, ist the cast between them bit-identical (or is to big
                      unsigned in signed undef)?
                      >
                      are all three chars (char, signed char, unsigned char) on every
                      plattform the same size?
                      >
                      is there a best practise to stream char plattform independend?
                      >
                      I'm not sure I understand your question; but I think the quick answer
                      is 'no'; at the very least you must consider endianess issues.
                      There are no endian issues to consider with 8-bit data. So the quick
                      answer is "yes", int8_t and uint8_t (unlike "char") are guaranteed to
                      use two's complement integer representation.

                      Greg

                        Comment

                        • Jack Klein
                          #7
                          Re: int8_t/uint8_t

                          On Thu, 03 Jul 2008 08:30:22 +0200, Chris Forone <4one@gmx.atwro te
                          in comp.lang.c++:
                          hello group,
                          >
                          is the cast of int8_t and uint8_t in char for streaming in both
                          directions (put(), get()) defined/plattform independent?
                          >
                          i have read here in the forum, that int8_t and uint8_t are guaranteed 2s
                          complement, ist the cast between them bit-identical (or is to big
                          unsigned in signed undef)?
                          People tend to say that, but they're wrong, of course. The exact
                          width integer types aren't actually part of standard C++ yet, but they
                          soon will be.

                          As defined in C, int#_t is required to be a signed integer type of the
                          specified number of bits with no trap representations and no padding
                          bits. It uses 2's complement for representing negative values.

                          But uint#_t types only hold unsigned values. They cannot represent
                          negative values, so they aren't ever 2's complement, 1's complement,
                          or sign and magnitude. These three things only apply to signed
                          integer types, and never to unsigned integer types.

                          --
                          Jack Klein
                          Home: http://JK-Technology.Com
                          FAQs for
                          comp.lang.c http://c-faq.com/
                          comp.lang.c++ http://www.parashift.com/c++-faq-lite/
                          alt.comp.lang.l earn.c-c++
                          http://www.club.cc.cmu.edu/~ajo/docs/FAQ-acllc.html

                            Comment

                            Previous template Next
                            Working...