Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • World
  • Users
  • Groups
Skins
  • Light
  • Cerulean
  • Cosmo
  • Flatly
  • Journal
  • Litera
  • Lumen
  • Lux
  • Materia
  • Minty
  • Morph
  • Pulse
  • Sandstone
  • Simplex
  • Sketchy
  • Spacelab
  • United
  • Yeti
  • Zephyr
  • Dark
  • Cyborg
  • Darkly
  • Quartz
  • Slate
  • Solar
  • Superhero
  • Vapor

  • Default (No Skin)
  • No Skin
Collapse
Code Project
  1. Home
  2. Other Discussions
  3. The Weird and The Wonderful
  4. Misaligned elephants

Misaligned elephants

Scheduled Pinned Locked Moved The Weird and The Wonderful
c++question
26 Posts 16 Posters 0 Views 1 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • S Sentenryu

    I'm the only one who thinks that if i've to read the code of the tools I use to be able to use it, i've no reason to use the tool? seriously, i hate when people pull open source to justify their lack of documentation.

    I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"

    M Offline
    M Offline
    Matthew Faithfull
    wrote on last edited by
    #16

    I very much agree. Open Source is not Open unless you can read it but a tool is no use as a tool if you have to fix it first before you can use it. In fairness most of GCC is reasonably or at least minimally documented, pragmas are an exceptionally bad area.

    "The secret of happiness is freedom, and the secret of freedom, courage." Thucydides (B.C. 460-400)

    S 1 Reply Last reply
    0
    • M Matthew Faithfull

      I very much agree. Open Source is not Open unless you can read it but a tool is no use as a tool if you have to fix it first before you can use it. In fairness most of GCC is reasonably or at least minimally documented, pragmas are an exceptionally bad area.

      "The secret of happiness is freedom, and the secret of freedom, courage." Thucydides (B.C. 460-400)

      S Offline
      S Offline
      Sentenryu
      wrote on last edited by
      #17

      I'm trying to work out how to use the SharpDX toolkit, even the documented areas have really poor descriptions of what they do and what they need... I'm starting to think i should just learn low level DirectX (I plan to, but once i've a high level understanding) Things like that make me think that open source means "Here's my code, you can use it, but you need to fix it first."

      I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"

      M R 2 Replies Last reply
      0
      • S Sentenryu

        I'm trying to work out how to use the SharpDX toolkit, even the documented areas have really poor descriptions of what they do and what they need... I'm starting to think i should just learn low level DirectX (I plan to, but once i've a high level understanding) Things like that make me think that open source means "Here's my code, you can use it, but you need to fix it first."

        I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"

        M Offline
        M Offline
        Matthew Faithfull
        wrote on last edited by
        #18

        This is often the case. I don't mind too much except when I go to fix the code and find it is an unformatted mess with little structure that is a pain in the eyes to read. Then I usually go and write my own. With DirectX I would say it depends how much COM you know. If you're happy with COM principles then just go straight to DirectX it's not at all difficult. If you hate or don't know COM then I would probably use with the toolkit unless it is hopeless.

        "The secret of happiness is freedom, and the secret of freedom, courage." Thucydides (B.C. 460-400)

        1 Reply Last reply
        0
        • S Sentenryu

          I'm the only one who thinks that if i've to read the code of the tools I use to be able to use it, i've no reason to use the tool? seriously, i hate when people pull open source to justify their lack of documentation.

          I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"

          B Offline
          B Offline
          BiggerDon
          wrote on last edited by
          #19

          Your English is as good as many of the programmers I know who speak it as it's first language...and as I tell people who complain about understanding people who speak/write English as a second/third/fourth... language, "It's better than my Portuguese (Hindi, Chinese, Russian...take your pick)."

          cat fud heer

          1 Reply Last reply
          0
          • S Sentenryu

            I'm trying to work out how to use the SharpDX toolkit, even the documented areas have really poor descriptions of what they do and what they need... I'm starting to think i should just learn low level DirectX (I plan to, but once i've a high level understanding) Things like that make me think that open source means "Here's my code, you can use it, but you need to fix it first."

            I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"

            R Offline
            R Offline
            RafagaX
            wrote on last edited by
            #20

            I've not used SharpDX, but my understanding is that a very thin wrapper around DirectX, so probably diving in the DirectX documentation can help you (actually DirectX documentation is full of examples that, hopefully, could be easily translated into C# or used directly in most cases).

            CEO at: - Rafaga Systems - Para Facturas - Modern Components for the moment...

            S 1 Reply Last reply
            0
            • M Matthew Faithfull

              If have a class containing this snippet declared in a C++ header file.

              protected:
              
                  \_tChar\* m\_p;
                  
                  //--------------------------------------------------------------------------------
                  struct sHeader
                  {
                      unsigned short usAlloc;
                      unsigned short usLen;
                  };
              
                  //--------------------------------------------------------------------------------
                  struct sFooter
                  {
                      unsigned short usRefCount;
                  };
              
                  //--------------------------------------------------------------------------------
                  virtual unsigned short HeaderByteSize( void ) const
                  {
                      return sizeof( sHeader );
                  }
              

              The header is used by half a dozen Dlls which are all part of a project. Instances of the class are created and passed around freely except it doesn't work. Because one dll has decided that sizeof( sHeader ) is 4 bytes as expected and another has decided that it's 16. The same header file, same build options and everything built together in a clean build. :mad::mad: The whole point of using sizeof( sHeader ) in the first place instead of just 4 was so that alignment wouldn't screw thing up. :mad::mad::mad: Now what do I do?

              "The secret of happiness is freedom, and the secret of freedom, courage." Thucydides (B.C. 460-400)

              S Offline
              S Offline
              Stuart Dootson
              wrote on last edited by
              #21

              To guard against issues like that where the size of objects REALLY mattered, I've always used a static_assert[^] to express static constraints like that:

              protected:

                  \_tChar\* m\_p;
                  
                  //--------------------------------------------------------------------------------
                  struct sHeader
                  {
                      unsigned short usAlloc;
                      unsigned short usLen;
                  };
              
                  static\_assert(sizeof(sHeader) == 4, "sHeader is an unexpected size!");
              
              
                  //--------------------------------------------------------------------------------
                  struct sFooter
                  {
                      unsigned short usRefCount;
                  };
              
                  //--------------------------------------------------------------------------------
                  virtual unsigned short HeaderByteSize( void ) const
                  {
                      return sizeof( sHeader );
                  }
              

              Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p CodeProject MVP for 2010 - who'd'a thunk it!

              M 1 Reply Last reply
              0
              • S Stuart Dootson

                To guard against issues like that where the size of objects REALLY mattered, I've always used a static_assert[^] to express static constraints like that:

                protected:

                    \_tChar\* m\_p;
                    
                    //--------------------------------------------------------------------------------
                    struct sHeader
                    {
                        unsigned short usAlloc;
                        unsigned short usLen;
                    };
                
                    static\_assert(sizeof(sHeader) == 4, "sHeader is an unexpected size!");
                
                
                    //--------------------------------------------------------------------------------
                    struct sFooter
                    {
                        unsigned short usRefCount;
                    };
                
                    //--------------------------------------------------------------------------------
                    virtual unsigned short HeaderByteSize( void ) const
                    {
                        return sizeof( sHeader );
                    }
                

                Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p CodeProject MVP for 2010 - who'd'a thunk it!

                M Offline
                M Offline
                Matthew Faithfull
                wrote on last edited by
                #22

                A good point, thanks. I have a static_assert and I should be using it.

                "The secret of happiness is freedom, and the secret of freedom, courage." Thucydides (B.C. 460-400)

                1 Reply Last reply
                0
                • R RafagaX

                  I've not used SharpDX, but my understanding is that a very thin wrapper around DirectX, so probably diving in the DirectX documentation can help you (actually DirectX documentation is full of examples that, hopefully, could be easily translated into C# or used directly in most cases).

                  CEO at: - Rafaga Systems - Para Facturas - Modern Components for the moment...

                  S Offline
                  S Offline
                  Sentenryu
                  wrote on last edited by
                  #23

                  the toolkit is a high level abstraction like XNA, the wrapper part is actually well documented with references to the unmanaged documentation and descriptions of the small differences.

                  I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241 "'Sophisticated platform' typically means 'I have no idea how it works.'"

                  1 Reply Last reply
                  0
                  • M Matthew Faithfull

                    YvesDaoust wrote:

                    Could it be a struct member alignment option silently set in a preceding header file

                    I suspect it might be just that, but leaking from a Windows header. Including pulls in which in this case is a project header not a system header. My guess is that the string support code is being included in the middle of a windows header section that for some reason has different alignment options. Tracking it down or doing anything about it would be rather difficult though. I've worked round this one but I'll be on the lookout next time and also need to get pragma pack support into my Compiler support library as soon as I can.

                    "The secret of happiness is freedom, and the secret of freedom, courage." Thucydides (B.C. 460-400)

                    R Offline
                    R Offline
                    Ralph Little
                    wrote on last edited by
                    #24

                    Yes, it also occurs to me that your core problem is not the size but the inconsistency. I would look for a platform specific solution to this problem rather than trying to find a platform generic packing instruction. Good luck anyway.

                    M 1 Reply Last reply
                    0
                    • M Matthew Faithfull

                      If have a class containing this snippet declared in a C++ header file.

                      protected:
                      
                          \_tChar\* m\_p;
                          
                          //--------------------------------------------------------------------------------
                          struct sHeader
                          {
                              unsigned short usAlloc;
                              unsigned short usLen;
                          };
                      
                          //--------------------------------------------------------------------------------
                          struct sFooter
                          {
                              unsigned short usRefCount;
                          };
                      
                          //--------------------------------------------------------------------------------
                          virtual unsigned short HeaderByteSize( void ) const
                          {
                              return sizeof( sHeader );
                          }
                      

                      The header is used by half a dozen Dlls which are all part of a project. Instances of the class are created and passed around freely except it doesn't work. Because one dll has decided that sizeof( sHeader ) is 4 bytes as expected and another has decided that it's 16. The same header file, same build options and everything built together in a clean build. :mad::mad: The whole point of using sizeof( sHeader ) in the first place instead of just 4 was so that alignment wouldn't screw thing up. :mad::mad::mad: Now what do I do?

                      "The secret of happiness is freedom, and the secret of freedom, courage." Thucydides (B.C. 460-400)

                      J Offline
                      J Offline
                      jschell
                      wrote on last edited by
                      #25

                      Matthew Faithfull wrote:

                      Now what do I do?

                      I would start by figuring out what in fact is different in that build. Might also help to investigate what is actually driving the size difference. Presumably packing, or lack thereof, however there is another option.

                      1 Reply Last reply
                      0
                      • R Ralph Little

                        Yes, it also occurs to me that your core problem is not the size but the inconsistency. I would look for a platform specific solution to this problem rather than trying to find a platform generic packing instruction. Good luck anyway.

                        M Offline
                        M Offline
                        Member 4608898
                        wrote on last edited by
                        #26

                        Is this on a 16-bit, 32-bit or 64 bit environment? If you are using Visual Studio, check the preprocessor directives in all the projects. Also check the code generation struct member alignment. I've had this before: all projects just used default settings except some were VS6, some were VS2003 and some were VS2005. I just got random unexplanable crashes, so, like you, I decided to look at the sizeof things and they were very different. Nowadays I avoid such things by not having inline functions. It may run slower but at least you don't spend weeks trying to figure out stuff like this.

                        1 Reply Last reply
                        0
                        Reply
                        • Reply as topic
                        Log in to reply
                        • Oldest to Newest
                        • Newest to Oldest
                        • Most Votes


                        • Login

                        • Don't have an account? Register

                        • Login or register to search.
                        • First post
                          Last post
                        0
                        • Categories
                        • Recent
                        • Tags
                        • Popular
                        • World
                        • Users
                        • Groups