Executable Wikipedia. This article is about a general type of computer file. For the specific file type used in some operating systems, see. In computing, executable code or an executable file or executable program, sometimes simply referred to as an executable or binary, causes a computer to perform indicated tasks according to encoded instructions,1 as opposed to a data file that must be parsed by a program to be meaningful. The exact interpretation depends upon the use while instructions is traditionally taken to mean machine code instructions for a physical CPU, in some contexts a file containing bytecode or scripting language instructions may also be considered executable. Generation of executable fileseditWhile an executable file can be hand coded in machine language, it is far more usual to develop software as source code in a high level language easily understood by humans, or in some cases in assembly language, which remains human readable while being more closely associated with machine code instructions. The high level language is compiled into either an executable machine code file or a non executable machine code object file of some sort the equivalent process on assembly language source code is called assembly. Several object files are linked to create the executable. Object files, executable or not, are typically in a container format, such as Executable and Linkable Format ELF. This structures the generated machine code, for example dividing it into sections such as the. In order to be executed by the system such as an operating system, firmware, or boot loader, an executable file must conform to the systems Application Binary Interface ABI. Most simply a file is executed by loading the file into memory and simply jumping to the start of the address space and executing from there, but in more complicated interfaces executable files have additional metadata, specifying a separate entry point. In computing, executable code or an executable file or executable program, sometimes simply referred to as an executable or binary, causes a computer to perform. For example, in ELF, the entry point is specified in the header in the eentry field, which specifies the virtual memory address at which to start execution. In the GCC GNU Compiler Collection this field is set by the linker based on the start symbol. Executable files typically also include a runtime system, which implements runtime language features such as task scheduling, exception handling, calling static constructors and destructors, etc. and interactions with the operating system, notably passing arguments, environment, and returning an exit status, together with other startup and shutdown features such as releasing resources like file handles. For C, this is done by linking in the crt. Executable files thus normally contain significant additional machine code beyond that directly generated from the specific source code. In some cases it is desirable to omit this, for example for embedded systems development or simply to understand how compilation, linking, and loading work. In C this can be done by omitting the usual runtime, and instead explicitly specifying a linker script, which generates the entry point and handles startup and shutdown, such as calling main to start and returning exit status to kernel at end. 2See alsoeditReferenceseditExternal linksedit.
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