Application binary interface

<h2 id="description">Description</h2>
Interface aspects covered by an ABI include:

<ul><li><a href="/facts/Processor_(computing)/z3wPljrI">Processor</a> <a href="/facts/Instruction_set/8p8vwUeE">instruction set</a>, with details like register file structure, <a href="/facts/Computer_memory/hQKVQ51J">memory</a> access types, etc.</li>
<li>Size, layout, and <a href="/facts/Data_structure_alignment/Bqk6zMNS">alignment</a> of basic <a href="/facts/Data_type/fcx5hgVL">data types</a> that the processor can directly access</li>
<li><a href="/facts/Calling_convention/FtzN2BKj">Calling convention</a>, which controls how the arguments of <a href="/facts/Function_(programming)/9vFJrg0A">functions</a> are passed, and return values retrieved; for example, it controls the following:
<ul><li>How the <a href="/facts/Call_stack/1sMt713v">call stack</a> is organized</li>
<li>Whether all parameters are passed on the call stack, or some are passed in registers</li>
<li>Which registers are used for which function parameters</li>
<li>Whether the first function parameter passed on the call stack is pushed first or last</li>
<li>Whether the caller or callee is responsible for cleaning up the call stack after the function call</li></ul></li>
<li><a href="/facts/Name_mangling/br0AH0zP">Name mangling</a><a class="footnote-ref" id="fnref:1" href="#fn:1">1</a></li>
<li><a href="/facts/Exception_handling/VrJxgb9r">Exception</a> propagation<a class="footnote-ref" id="fnref:2" href="#fn:2">2</a></li>
<li>How an application should make <a href="/facts/System_call/NW44AFJr">system calls</a> to the operating system, and if the ABI specifies direct system calls rather than procedure calls to system call <a href="/facts/Method_stub/oG08a8Ad">stubs</a>, the system call numbers</li>
<li>In the case of a complete operating system ABI, the binary format of <a href="/facts/Object_file/sFBvosE4">object files</a>, program libraries, etc.</li></ul>
ABIs include the <a href="/facts/Intel_Binary_Compatibility_Standard/8BELVUCf">Intel Binary Compatibility Standard</a> (iBCS)<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a> and the <a href="/facts/System_V_Release_4/Epm6GEY4">System V Release 4</a> ABIs for various instruction sets.

<h2 id="embedded-abi">Embedded ABI</h2>
An embedded ABI (EABI), used on an <a href="/facts/Embedded_operating_system/0ue9DzHw">embedded operating system</a>, specifies aspects such as <a href="/facts/File_format/qrXbwJaH">file formats</a>, data types, register usage, <a href="/facts/Stack_frame/1sMt713v">stack frame</a> organization, and function parameter passing of an <a href="/facts/Embedded_system/a4muX1wU">embedded</a> software program.
Each compiler and <a href="/facts/Assembly_language/7XuV0cla">assembler</a> that supports an EABI creates <a href="/facts/Object_code/Sht3h4lW">object code</a> that is compatible with code generated by other such compilers and assemblers. This allows developers to link libraries generated by one compiler with object code generated by another.
Typically, an EABI is optimized for performance for the limited resources of the target embedded system. Therefore, an EABI may omit abstractions between <a href="/facts/User_space_and_kernel_space/0yIzMY8t">kernel and user space</a> typically found in <a href="/facts/Desktop_computer/edFPINdK">desktop</a> operating systems. For example, <a href="/facts/Dynamic_linking/4vQ2J2xS">dynamic linking</a> may be avoided to allow smaller executables and faster loading, fixed register usage allows more compact stacks and kernel calls, and running the application in privileged mode allows direct access to custom hardware operation without the indirection of calling a device driver.<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a> The choice of EABI can affect performance.<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a><a class="footnote-ref" id="fnref:6" href="#fn:6">6</a>
Widely used EABIs include the <a href="/facts/PowerPC/DqmM9y50">PowerPC</a>,<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a> <a href="/facts/Arm_architecture/SALsYA79">Arm</a>,<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a> and <a href="/facts/MIPS_architecture/efV4KgK4">MIPS</a> EABIs.<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a> Specific software implementations like the C library may impose additional limitations to form more concrete ABIs; one example is the GNU OABI and EABI for ARM, both of which are subsets of the ARM EABI.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a>

<h2 id="see-also">See also</h2>
<ul>
<li>Computer programming portal</li></ul>
<ul><li><a href="/facts/Binary-code_compatibility/7lkFAUfv">Binary-code compatibility</a> – Ability of a computer system to run the same code as another computer system</li>
<li><a href="/facts/Bytecode/EPkMFR7M">Bytecode</a> – Form of instruction set designed to be run by a software interpreter</li>
<li><a href="/facts/Comparison_of_application_virtualization_software/P82vGmuz">Comparison of application virtualization software</a></li>
<li><a href="/facts/Debug_symbol/ITvjepr0">Debug symbol</a> – Type of identifier in computer science</li>
<li><a href="/facts/Foreign_function_interface/ntAxkhK0">Foreign function interface</a> – Interface to call functions from other programming languages</li>
<li><a href="/facts/Language_binding/V5HW4Wr4">Language binding</a> – Software library that allows using another library coded in another programming language</li>
<li><a href="/facts/Native_(computing)/yNez4jAK">Native (computing)</a> – Software that operates directly in a given context</li>
<li><a href="/facts/Opaque_pointer/NNc0Nm1J">Opaque pointer</a> – Opaque data type which stores a memory address</li>
<li><a href="/facts/PowerOpen_Environment/AjDjIKVV">PowerOpen Environment</a> – Open standard by AIM alliance</li>
<li><a href="/facts/Symbol_table/ILc0WE9u">Symbol table</a> – Data structure used by a language translator such as a compiler or interpreter</li>
<li><a href="/facts/SWIG/A8Q6IxLt">SWIG</a> – Open-source programming tool</li>
<li><a href="/facts/Visual_C%252B%252B/RM3sbYw5">Visual C++ Compatibility</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://community.kde.org/Policies/Binary_Compatibility_Issues_With_C%2B%2B">Policies/Binary Compatibility Issues With C++</a> – a compendium of development rules of thumb for not breaking binary compatibility between library releases</li>
<li><a href="https://developer.apple.com/library/content/documentation/DeveloperTools/Conceptual/LowLevelABI/000-Introduction/introduction.html">OS X ABI Function Call Guide</a></li>
<li><a href="http://wiki.debian.org/ArmEabiPort">Debian ARM EABI port</a></li>
<li><a href="http://www.uclibc.org/">μClib: Motorola 8/16-bit embedded ABI</a></li>
<li><a href="https://web.archive.org/web/20080528070803/http://www.x86-64.org/documentation.html">AMD64 (x86-64) Application Binary Interface</a> at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a> (archived 2008-05-28)</li>
<li><a href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ihi0036b/index.html">Application Binary Interface (ABI) for the ARM Architecture</a></li>
<li><a href="https://sourceware.org/legacy-ml/binutils/2003-06/msg00436.html">MIPS EABI documentation</a></li>
<li><a href="https://web.archive.org/web/20150114065444/http://www.oracle.com/technetwork/server-storage/solaris10/about-amd64-abi-141142.html">Sun Studio 10 Compilers and the AMD64 ABI</a> at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a> (archived 2015-01-14) – a summary and comparison of some popular ABIs</li>
<li><a href="https://www.nxp.com/docs/en/reference-manual/MCOREABISM.pdf">M•CORE Applications Binary Interface Standards Manual</a> for the Freescale <a href="/facts/M%25C2%25B7CORE/Tll5Yu4q">M·CORE</a> processors</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">"Itanium C++ ABI". (compatible with multiple architectures) <a href="https://itanium-cxx-abi.github.io/cxx-abi/" target="_blank">https://itanium-cxx-abi.github.io/cxx-abi/</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">"Itanium C++ ABI: Exception Handling". (compatible with multiple architectures) <a href="http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html" target="_blank">http://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">"Intel Binary Compatibility Standard (iBCS)". <a href="http://www.everything2.com/index.pl?node=iBCS" target="_blank">http://www.everything2.com/index.pl?node=iBCS</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">"EABI Summary". PowerPC Embedded Application Binary Interface: 32-Bit Implementation (PDF) (Version 1.0 ed.). Freescale Semiconductor, Inc. 1 October 1995. pp. 28–30. <a href="http://www.nxp.com/docs/en/application-note/PPCEABI.pdf" target="_blank">http://www.nxp.com/docs/en/application-note/PPCEABI.pdf</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">"Debian ARM accelerates via EABI port". Linuxdevices.com. 16 October 2016. Archived from the original on 21 January 2007. Retrieved 11 October 2007. <a href="https://web.archive.org/web/20070121183413/http://www.linuxdevices.com/news/NS9048137234.html" target="_blank">https://web.archive.org/web/20070121183413/http://www.linuxdevices.com/news/NS9048137234.html</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Andrés Calderón and Nelson Castillo (14 March 2007). "Why ARM's EABI matters". Linuxdevices.com. Archived from the original on 31 March 2007. Retrieved 11 October 2007. <a href="https://web.archive.org/web/20070331193917/http://www.linuxdevices.com/articles/AT5920399313.html" target="_blank">https://web.archive.org/web/20070331193917/http://www.linuxdevices.com/articles/AT5920399313.html</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">"EABI Summary". PowerPC Embedded Application Binary Interface: 32-Bit Implementation (PDF) (Version 1.0 ed.). Freescale Semiconductor, Inc. 1 October 1995. pp. 28–30. <a href="http://www.nxp.com/docs/en/application-note/PPCEABI.pdf" target="_blank">http://www.nxp.com/docs/en/application-note/PPCEABI.pdf</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">"ABI for the Arm Architecture". Developer.arm.com. Retrieved 4 February 2020. <a href="https://developer.arm.com/architectures/system-architectures/software-standards/abi" target="_blank">https://developer.arm.com/architectures/system-architectures/software-standards/abi</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Eric Christopher (11 June 2003). "mips eabi documentation". binutils@sources.redhat.com (Mailing list). Retrieved 19 June 2020. <a href="https://sourceware.org/legacy-ml/binutils/2003-06/msg00436.html" target="_blank">https://sourceware.org/legacy-ml/binutils/2003-06/msg00436.html</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">"ArmEabiPort". Debian Wiki. Strictly speaking, both the old and new ARM ABIs are subsets of the ARM EABI specification, but in everyday usage the term "EABI" is used to mean the new one described here and "OABI" or "old-ABI" to mean the old one. <a href="https://wiki.debian.org/ArmEabiPort" target="_blank">https://wiki.debian.org/ArmEabiPort</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
</ol>

Application binary interface open-in-new

Application binary interface