In computing, source code is any collection of code, possibly with comments, written in a human readable programming language , usually as plain text. The source code of a program is specifically designed to facilitate the work of computer programmers, which determines the actions most computers must perform by writing source code. The source code is often converted by an assembler or compiler into a binary machine code that is understood by a computer. The machine code may then be stored for execution at a later time. Alternatively, the source code can be interpreted and thus immediately executed.
Most application software is distributed in a form that contains only executable files. If the source code is entered, it will be useful for users, programmers or system administrators, anyone who may want to learn or modify the program.
Video Source code
Definition
The Linux Information Project defines the source code as:
The source code (also referred to as the source or code) is a software version as originally written (ie typed to the computer) by humans in plain text (ie human-readable alphanumeric characters).
The idea of ​​source code can also be taken more broadly, to include machine code and notation in graphical language, both of which are not textual. Examples of articles presented at the IEEE annual conference and Source Code Analysis and Manipulation:
For clarity purposes, "source code" is defined as a description of a fully executable software system. It is therefore strongly interpreted to include machine code, a very high level language and an executable graphical representation of the system.
Often there are several steps in the translation of the program or minification between the original source code that is typed by humans and executable programs. While some, such as FSF, argue that the intermediary file "is not a real source code and is not counted as source code", others feel comfortable referring to each intermediate file as source code for the next step.
Maps Source code
History
The earliest programs for stored program computers are entered in the binary via the front panel computer switch. This first generation programming language has no distinction between source code and machine code.
When IBM first offered the software to work with the machine, the source code was supplied at no additional cost. At that time, development costs and supporting software are included in the price of the hardware. For decades, IBM distributed the source code with the license of its software product, after 1999.
Most early computer magazines publish the source code as a type-in ​​program.
Sometimes the entire source code for large programs is published as hardcover books, such as Computers and Typesetting , vol. B: TeX, Program by Donald Knuth, Source Code PGP and Internal by Philip Zimmermann,
Organization
The source code that is the program is usually stored in one or more text files stored on the computer hard disk; usually these files are carefully compiled into directory trees, known as source tree . The source code can also be stored in the database (as is common for stored procedures) or elsewhere.
The source code for a particular piece of software may be contained in a single file or multiple files. Although the practice is not common, program source code can be written in different programming languages. For example, a program written primarily in C programming languages, may have sections written in assembly language for optimization purposes. It also allows for some components of a software to be written and compiled separately, in random programming languages, and then integrated into software using a technique called linking libraries. In some languages, such as Java, this can be done at run time (each class is compiled into a separate file linked by the translator at runtime).
Yet another method is to make the main program translator for the programming language, whether designed specifically for the intended application or general purpose, and then write most of the actual user function as a macro or other form of add-in in this language, the approach taken eg by the GNU Emacs text editor.
The codebase of a computer programming project is a larger collection of all source code of all the computer programs that make up the project. It is common practice to maintain the code base in the version control system. A fairly complex software usually requires some compilation or assembly, sometimes tens or even hundreds, of different source code files. In this case, instructions for compilation, such as Makefile, are included with the source code. It describes the programming relationships between source code files, and contains information about how they will be compiled.
The revision control system is another tool often used by developers for the maintenance of the source code.
Destination
The source code is primarily used as input for processes that produce executable programs (ie, compiled or interpreted). It is also used as a method of communicating algorithms between people (eg, code snippets in books).
Computer programmers often find it helpful to review existing source code to learn about programming techniques. Sharing source code among developers is often cited as a factor that contributes to the maturation of their programming skills. Some people regard the source code as an expressive artistic medium.
Porting software to other computer platforms is usually very difficult without source code. Without source code for certain software, portability is generally costly in computation. Possible porting options include binary and emulation of the original platform.
Decompilation of executable programs can be used to generate source code, either in assembly code or in high-level languages.
Programmers often adapt the source code of one piece of software to use in another project, a concept known as reusable software.
Legal aspects
This situation varies worldwide, but in the United States before 1974, the software and its source code were not copyrighted and therefore always the public domain software.
In 1974, the US Commission on the Use of New Technology from Copyright Works (CONTU) ruled that "computer programs, to the extent that they embody the original creations of authors, are the exact subject of copyright".
In 1983 in the United States court case Apple v. Franklin specified that the same is applied to the object code; and that the Copyright Act gives the computer program the copyright status of a literary work.
In 1999, in the case of the United States court of Bernstein v. The United States is further stipulated that the source code may be regarded as a constitutionally protected form of freedom of speech. Proponents of freedom of opinion argue that because the source code conveys information to the programmer, written in the language, and can be used to share humor and other artistic activities, it is a form of protected communication.
License
A writer of non-trivial jobs such as software, has several exclusive rights, including copyright for source code and object code. The author has the right and possibility to give its customers and users the software some of its exclusive rights in the form of software licenses. The software, and the accompanying source code, may be associated with some licensing paradigm; the most important difference is open source vs. proprietary software. This is done by including a copyright notice stating the terms of licensing. If no notifications are found, then the default All rights reserved is implied.
In general, software is open source if free source code is used, distributed, modified and learned, and belongs if the source code is kept private, or privately owned and restricted. One of the first software licenses published and to explicitly grant this freedom was the GNU General Public License in 1989; The BSD license is another early example from 1990.
For proprietary software, the provisions of various copyright laws, confidentiality and patents are used to keep the source code closed. In addition, many retail software comes with end-user license agreements (EULA) that normally prohibit decompile, reverse engineer, analysis, modification, or avoid copy protection. Source code protection type - beyond traditional compilation to object code - including encryption code, obfuscation code or morphing code.
Quality
The way the program is written can have important consequences for the managers. Encoding conventions, which emphasize readability and some language-specific conventions, are intended for the maintenance of software source code, which involves debugging and updating. Other priorities, such as program execution speed, or the ability to compile programs for multiple architectures, often make code readings of lesser importance, since the quality of the code generally depends on the purpose of
See also
- Bytecode
- Code as data
- Encoding convention
- Computer code
- Old code
- Machine code
- Markup language
- Unclear code
- Object code
- Open source software The package
- (package management system)
- Programming language
- The source code repository
- Syntax highlighting
- Visual programming languages ​​
References
- (VEW04) "Using Decompilers for Real World Source Restoration", M. Van Emmerik and T. Waddington, Working Conference on Reverse Engineering , Delft, Netherlands, 9-12 November 2004 Long version of paper.
External links
- Definition of Source Code by Linux Information Project (LINFO)
- "Compulsory accreditation system for IT security products". MetaFilter.com. September 22, 2008.
will introduce a regulation requiring foreign companies to disclose confidential information about digital home appliances and other products from May next year, the Yomiuri Shimbun quoted unnamed sources as saying. If a company refuses to disclose information, China will ban it from exporting products to the Chinese market or producing or selling them in China, the newspaper said.
- The same program is written in multiple languages ​​
- Obfuscator Javascript
Source of the article : Wikipedia
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