ANSI C, ISO C, and Standard C are successive standards for the C programming language published by the American National Standards Institute (ANSI) and ISO/IEC JTC 1/SC 22/WG 14 of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). Historically, the names referred specifically to the original and best-supported version of the standard. Software developers writing in C are encouraged to conform to the standards, as doing so helps portability between compilers.
Character encoding is the process of assigning numbers to graphical characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using digital computers. The numerical values that make up a character encoding are known as "code points" and collectively comprise a "code space", a "code page", or a "character map".
ISO/IEC 8859-1:1998, Information technology—8-bit single-byte coded graphic character sets—Part 1: Latin alphabet No. 1, is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 1987. ISO/IEC 8859-1 encodes what it refers to as "Latin alphabet no. 1", consisting of 191 characters from the Latin script. This character-encoding scheme is used throughout the Americas, Western Europe, Oceania, and much of Africa. It is the basis for some popular 8-bit character sets and the first two blocks of characters in Unicode.
Unicode, formally The Unicode Standard, is a text encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 of the standard defines 154998 characters and 168 scripts used in various ordinary, literary, academic, and technical contexts.
UTF-8 is a character encoding standard used for electronic communication. Defined by the Unicode Standard, the name is derived from Unicode Transformation Format – 8-bit. Almost every web page is stored in UTF-8.
UTF-16 (16-bit Unicode Transformation Format) is a character encoding capable of encoding all 1,112,064 valid code points of Unicode (in fact this number of code points is dictated by the design of UTF-16). The encoding is variable-length, as code points are encoded with one or two 16-bit code units. UTF-16 arose from an earlier obsolete fixed-width 16-bit encoding now known as "UCS-2" (for 2-byte Universal Character Set), once it became clear that more than 216 (65,536) code points were needed, including most emoji and important CJK characters such as for personal and place names.
In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language.
UTF-32 (32-bit Unicode Transformation Format) is a fixed-length encoding used to encode Unicode code points that uses exactly 32 bits (four bytes) per code point (but a number of leading bits must be zero as there are far fewer than 232 Unicode code points, needing actually only 21 bits). In contrast, all other Unicode transformation formats are variable-length encodings. Each 32-bit value in UTF-32 represents one Unicode code point and is exactly equal to that code point's numerical value.
A text file is a kind of computer file that is structured as a sequence of lines of electronic text. A text file exists stored as data within a computer file system.
ISO/IEC 8859-9:1999, Information technology — 8-bit single-byte coded graphic character sets — Part 9: Latin alphabet No. 5, is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 1989. It is designated ECMA-128 by Ecma International and TS 5881 as a Turkish standard. It is informally referred to as Latin-5 or Turkish. It was designed to cover the Turkish language, designed as being of more use than the ISO/IEC 8859-3 encoding. It is identical to ISO/IEC 8859-1 except for the replacement of six Icelandic characters with characters unique to the Turkish alphabet. And the uppercase of i is İ; the lowercase of I is ı.
ISO/IEC 2022Information technology—Character code structure and extension techniques, is an ISO/IEC standard in the field of character encoding. It is equivalent to the ECMA standard ECMA-35, the ANSI standard ANSI X3.41 and the Japanese Industrial Standard JIS X 0202. Originating in 1971, it was most recently revised in 1994.
Extended Unix Code (EUC) is a multibyte character encoding system used primarily for Japanese, Korean, and simplified Chinese (characters).
A wide character is a computer character datatype that generally has a size greater than the traditional 8-bit character. The increased datatype size allows for the use of larger coded character sets.
Registration authorities (RAs) exist for many standards organizations, such as ANNA, the Object Management Group, W3C, and others. In general, registration authorities all perform a similar function, in promoting the use of a particular standard through facilitating its use. This may be by applying the standard, where appropriate, or by verifying that a particular application satisfies the standard's tenants. Maintenance agencies, in contrast, may change an element in a standard based on set rules – such as the creation or change of a currency code when a currency is created or revalued. The Object Management Group has an additional concept of certified provider, which is deemed an entity permitted to perform some functions on behalf of the registration authority, under specific processes and procedures documented within the standard for such a role.
The Common Locale Data Repository (CLDR) is a project of the Unicode Consortium to provide locale data in XML format for use in computer applications. CLDR contains locale-specific information that an operating system will typically provide to applications. CLDR is written in the Locale Data Markup Language (LDML).
The C++ programming language has support for string handling, mostly implemented in its standard library. The language standard specifies several string types, some inherited from C, some designed to make use of the language's features, such as classes and RAII. The most-used of these is std::string.
An IETF BCP 47 language tag is a standardized code that is used to identify human languages on the Internet. The tag structure has been standardized by the Internet Engineering Task Force (IETF) in Best Current Practice (BCP) 47; the subtags are maintained by the IANA Language Subtag Registry.
C11, is a past standard for the C programming language. It replaced C99 and has been superseded by C17. C11 mainly standardizes features already supported by common contemporary compilers, and includes a detailed memory model to better support multiple threads of execution. Due to delayed availability of conforming C99 implementations, C11 makes certain features optional, to make it easier to comply with the core language standard.
Microsoft was one of the first companies to implement Unicode in their products. Windows NT was the first operating system that used "wide characters" in system calls. Using the UCS-2 encoding scheme at first, it was upgraded to the variable-width encoding UTF-16 starting with Windows 2000, allowing a representation of additional planes with surrogate pairs. However Microsoft did not support UTF-8 in its API until May 2019.
The C programming language has a set of functions implementing operations on strings in its standard library. Various operations, such as copying, concatenation, tokenization and searching are supported. For character strings, the standard library uses the convention that strings are null-terminated: a string of n characters is represented as an array of n + 1 elements, the last of which is a "NUL character" with numeric value 0.
