C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  ABI? Goto page 1, 2  Next          C++Talk.NET Forum Index -> C++ Language (Moderated) View previous topic :: View next topic   Author Message Al Stevens Guest Posted: Tue Dec 09, 2003 7:59 pm    Post subject: ABI? I must ask a dumb question here. I've been away from C++ for a while. In recent readings, the acronym ABI popped up. A google search turns it up all over the place, but never defined anywhere and never in a context where I can infer exactly what it means. The acronym is not mentioned in my PDF copy of the standard. Anyway, what does it mean? Al Stevens http://www.alstevens.com [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Alberto L Guest Posted: Tue Dec 09, 2003 10:09 pm    Post subject: Re: ABI? Hi, see http://gcc.gnu.org/ml/libstdc++/2001-11/msg00063.html {However could everyone please avoid posting just a URI, a sentence explaining why it is relevant is helpful. -mod} [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Hyman Rosen Guest Posted: Tue Dec 09, 2003 10:09 pm    Post subject: Re: ABI? Al Stevens wrote: Quote: ABI, what does it mean? Application Binary Interface In this context, it is an exhaustively detailed specification for how C++ structures are represented when compiled. This includes the layout of classes in memory, the layout of virtual tables, the format of exception hander information, the modification of vtable pointers during construction and destruction, parameter passing and return sequences, and detailed name mangling rules, including rules for mangling compiler-genertated entities such as the guards which ensure that static initializers run exactly once. Compilers which adhere to an ABI produce object files which can be linked with object files from other adherent compilers. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Stefan Heinzmann Guest Posted: Wed Dec 10, 2003 11:13 am    Post subject: Re: ABI? Al Stevens wrote: Quote: I must ask a dumb question here. I don't think it is dumb at all. Quote: I've been away from C++ for a while. In recent readings, the acronym ABI popped up. The acronym is quite old. You must have been away for a long while :-) Quote: A google search turns it up all over the place, but never defined anywhere and never in a context where I can infer exactly what it means. The acronym is not mentioned in my PDF copy of the standard. Anyway, what does it mean? It isn't defined in the C++ standard because the standard is not concerned with binary representations of C++ constructs. ABI means Application Binary Interface In prose, an ABI defines what is needed to interface the compiled code of an application to the compiled code of a library. In C times this meant to define the procedure call details (how parameters are passed and results returned), the representation of data types (how elementary types are stored, i.e. alignment, and the memory image of structs), and how names in the source code translate to names for the linker (i.e. some C compilers prepend an underscore to procedure names, some don't). In C++ there are more things to specify to ensure that applications can be linked to libraries: How is the virtual function call mechanism implemented (layout of the vtable, multiple inheritance etc.). What is the object layout in memory (this goes beyond simple structs: i.e. there's virtual and multiple inheritance to consider). How are exceptions handled (this includes the whole stack unwinding business). How is run-time-type-info represented (and, as a consequence, how does dynamic_cast work). There may be more things I overlooked. If two compilers for the same platform implement the above language features differently (and that is frequently the case), an application can not be linked successfully to a library that was compiled with the other compiler. This is particularly painful with shared libraries (or DLLs, however you name them). An ABI standard is meant to remove this complication. It is by definition platform specific (it doesn't make any sense to link an application compiled for a Mac to a library compiled for a Sun, for instance). It is meant to make different compilers on the same platform compatible to each other (so that you can link an application compiled with GCC with a library compiled with the Sun compiler, for instance). Without an ABI, a library vendor not wanting to distribute the library source code is faced with the problem of having to provide not just one version of the library per platform but one version per compiler on each of the supported platforms. This is very quickly getting unmanageable and presents a serious obstacle for library vendors. Cheers Stefan [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Al Stevens Guest Posted: Wed Dec 10, 2003 11:14 am    Post subject: Re: ABI? "Hyman Rosen" <hyrosen (AT) mail (DOT) com> wrote Quote: Al Stevens wrote: ABI, what does it mean? Application Binary Interface [snip] Quote: Compilers which adhere to an ABI produce object files which can be linked with object files from other adherent compilers. Thank you. Is this a Linux-only thing? Or has the C++ compiler community at large embraced it? Is it likely to be a part of the standard? Al Stevens http://www.alstevens.com [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Tnwmack Guest Posted: Wed Dec 10, 2003 11:34 am    Post subject: ABI? You should try out Google glossary http://labs.google.com/glossary it works really well for stuff like that. It came up with: Application binary interface Tweek [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Thorsten Ottosen Guest Posted: Wed Dec 10, 2003 11:37 am    Post subject: Re: ABI? "Hyman Rosen" <hyrosen (AT) mail (DOT) com> wrote Quote: Al Stevens wrote: Compilers which adhere to an ABI produce object files which can be linked with object files from other adherent compilers. And how many compilers currently support the same ABI? -Thorsten [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Jean-Marc Bourguet Guest Posted: Wed Dec 10, 2003 4:09 pm    Post subject: Re: ABI? "Al Stevens" <nobody (AT) home (DOT) com> writes: Quote: "Hyman Rosen" <hyrosen (AT) mail (DOT) com> wrote in message news:1071003495.1185 (AT) master (DOT) nyc.kbcfp.com... Al Stevens wrote: ABI, what does it mean? Application Binary Interface [snip] Compilers which adhere to an ABI produce object files which can be linked with object files from other adherent compilers. Thank you. Is this a Linux-only thing? Or has the C++ compiler community at large embraced it? Is it likely to be a part of the standard? By definition, an ABI specify things which are architecture and sometimes operating system specific. As far as I know, there has been one definition of a common ABI for IA-64 which is endorsed by most if not all producers of compilers for IA-64 (and most probably most OS builders are trying not to interfere with this ABI) and gcc use now the architecture independant part of that ABI for most (if not all) its targets. I know of no other tentative to create and publish an ABI for C++ which is common to several compiler producers. Yours, -- Jean-Marc [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Francis Glassborow Guest Posted: Wed Dec 10, 2003 4:23 pm    Post subject: Re: ABI? In article <aZrBb.58939$AM3.1084818 (AT) twister (DOT) tampabay.rr.com>, Al Stevens <nobody (AT) home (DOT) com> writes Quote: "Hyman Rosen" <hyrosen (AT) mail (DOT) com> wrote in message news:1071003495.1185 (AT) master (DOT) nyc.kbcfp.com... Al Stevens wrote: ABI, what does it mean? Application Binary Interface [snip] Compilers which adhere to an ABI produce object files which can be linked with object files from other adherent compilers. Thank you. Is this a Linux-only thing? Or has the C++ compiler community at large embraced it? Is it likely to be a part of the standard? 1) It is not a Linux only thing though ABIs are easier to provide on a platform by platform basis. 2) An ABI is outside the scope of an ISO language standard because it necessarily relies on things that are platform specific (such as endianness) -- Francis Glassborow ACCU Author of 'You Can Do It!' see http://www.spellen.org/youcandoit [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Antoun Kanawati Guest Posted: Wed Dec 10, 2003 8:15 pm    Post subject: Re: ABI? Al Stevens wrote: Quote: "Hyman Rosen" <hyrosen (AT) mail (DOT) com> wrote in message news:1071003495.1185 (AT) master (DOT) nyc.kbcfp.com... Al Stevens wrote: ABI, what does it mean? Application Binary Interface [snip] Compilers which adhere to an ABI produce object files which can be linked with object files from other adherent compilers. Thank you. Is this a Linux-only thing? Or has the C++ compiler community at large embraced it? Is it likely to be a part of the standard? It's not standard, since the standard does not specify the representations, mangling, or any of the other details. ABI (adherence, or lack thereof) usually comes up with compiler upgrades. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Al Stevens Guest Posted: Wed Dec 10, 2003 8:23 pm    Post subject: Re: ABI? "Francis Glassborow" <francis (AT) robinton (DOT) demon.co.uk> wrote Quote: 2) An ABI is outside the scope of an ISO language standard because it necessarily relies on things that are platform specific (such as endianness) So does int. My question wasn't meant to ask if any particular ABI would become part of the standard; rather whether the ABI concept itself be identified as something a compliant compiler ought to support. But I can see where they wouldn't want to get into that can of worms. Thanks. Al Stevens http://www.alstevens.com [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Ben Hutchings Guest Posted: Wed Dec 10, 2003 8:30 pm    Post subject: Re: ABI? Al Stevens wrote: Quote: "Hyman Rosen" <hyrosen (AT) mail (DOT) com> wrote in message news:1071003495.1185 (AT) master (DOT) nyc.kbcfp.com... Al Stevens wrote: ABI, what does it mean? Application Binary Interface [snip] Compilers which adhere to an ABI produce object files which can be linked with object files from other adherent compilers. Thank you. Is this a Linux-only thing? No. Quote: Or has the C++ compiler community at large embraced it? The standardisation of C++ ABIs started with the IA64 ABI which is used by C++ implementations for Linux and proprietary Unixes on Itanium processors. I don't think Microsoft follows it with VC++ for IA64 though. ARM has subsequently drawn up a similar ABI for their architecture, which is supported by most ARM tool vendors on a wide variety of operating systems. The GCC project has adopted ABIs based on the IA64 ABI for various other architectures and operating systems. Again, GCC is used on a wide variety of operating systems. On Windows, however, Visual C++ is the de-facto standard and its ABI is unpublished so it's difficult for other implementations to interoperate with it. A subset of the ABI has been reverse- engineered successfully and is supported by other implementations. Quote: Is it likely to be a part of the standard? I don't think so. There have been C ABIs for a long time and they have never been included in the standard. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Hyman Rosen Guest Posted: Wed Dec 10, 2003 8:36 pm    Post subject: Re: ABI? Al Stevens wrote: Quote: Thank you. Is this a Linux-only thing? Or has the C++ compiler community at large embraced it? Is it likely to be a part of the standard? By their nature, ABIs depend heavily on the architecture for which they're defined, and must interact with existing operating system infrastructure as well. The best you could hope for is that all compilers on a platform will follow a standard for that platform. It can never be part of the standard becaus ethe standard doesn't specify low-level implementation details. Also, as an example of problems that can occur, Microsoft has a patent on a particular form of object layout they use in their C++ compiler, so other vendors have made deliberately incompatible compilers so as to avoid having to pay roaylties. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Mogens Hansen Guest Posted: Thu Dec 11, 2003 11:40 am    Post subject: Re: ABI? "Thorsten Ottosen" <nesotto (AT) cs (DOT) auc.dk> wrote Quote: "Hyman Rosen" <hyrosen (AT) mail (DOT) com> wrote in message news:1071003495.1185 (AT) master (DOT) nyc.kbcfp.com... Al Stevens wrote: Compilers which adhere to an ABI produce object files which can be linked with object files from other adherent compilers. And how many compilers currently support the same ABI? Examples: Intel C++ for Windows supports the ABI of either Microsoft Visual C++ V6.0 Microsoft Visual C++ V7.0 (.NET 2002) native code Microsoft Visual C++ V7.1 (.NET 2001) native code for x86 processors in my experience that works fine in practice Intel C++ for Linux supports the ABI of g++ 3.2 for x86 and Itanium processors I only have little experience with that in practice. It's my impression that Itanium processor compilers are encorages to follow the same ABI (http://www.codesourcery.com/cxx-abi/) Kind regards Mogens Hansen [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Derek Guest Posted: Thu Dec 11, 2003 12:28 pm    Post subject: Re: ABI? Good answer, Stefan. That's the best explanation of ABI that I have seen yet. It seems to me that for a standard C++ ABI to succeed, compiler vendors would have to agree on many implementation details (data layout and alignment, member pointers, vtable layout, RTTI, function calling, mangling, exception handling, etc.). Agreement on so many points seems unlikely. Can anyone tell me if a standard C++ ABI has been adoped by on any platform? "Stefan Heinzmann" wrote... Quote: I must ask a dumb question here. I don't think it is dumb at all. I've been away from C++ for a while. In recent readings, the acronym ABI popped up. The acronym is quite old. You must have been away for a long while :-) A google search turns it up all over the place, but never defined anywhere and never in a context where I can infer exactly what it means. The acronym is not mentioned in my PDF copy of the standard. Anyway, what does it mean? It isn't defined in the C++ standard because the standard is not concerned with binary representations of C++ constructs. ABI means Application Binary Interface {quote of rest of post snipped by mod/fgw} Cheers Stefan [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. 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