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Strlcpy
The C programming language has a set of functions implementing operations on strings (character strings and byte 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 characters is represented as an array of elements, the last of which is a " character" with numeric value 0. The only support for strings in the programming language proper is that the compiler translates quoted string constants into null-terminated strings. Definitions A string is defined as a contiguous sequence of code units terminated by the first zero code unit (often called the ''NUL'' code unit). This means a string cannot contain the zero code unit, as the first one seen marks the end of the string. The ''length'' of a string is the number of code units before the zero code unit. The memory occupied by a string is alwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
String (computer Science)
In computer programming, a string is traditionally a sequence of character (computing), characters, either as a literal (computer programming), literal constant or as some kind of Variable (computer science), variable. The latter may allow its elements to be Immutable object, mutated and the length changed, or it may be fixed (after creation). A string is often implemented as an array data structure of bytes (or word (computer architecture), words) that stores a sequence of elements, typically characters, using some character encoding. More general, ''string'' may also denote a sequence (or List (abstract data type), list) of data other than just characters. Depending on the programming language and precise data type used, a variable (programming), variable declared to be a string may either cause storage in memory to be statically allocated for a predetermined maximum length or employ dynamic allocation to allow it to hold a variable number of elements. When a string appears lit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Standard Library
The C standard library, sometimes referred to as libc, is the standard library for the C (programming language), C programming language, as specified in the ISO C standard.International Organization for Standardization, ISO/International Electrotechnical Commission, IEC (2018). ''C17 (C standard revision), ISO/IEC 9899:2018(E): Programming Languages - C §7'' Starting from the original ANSI C standard, it was developed at the same time as the C POSIX library, which is a superset of it. Since ANSI C was adopted by the International Organization for Standardization, the C standard library is also called the ISO C library. The C standard library provides macro (computer science), macros, Data type, type definitions and Function (computer programming), functions for tasks such as character string (computer science), string manipulation, mathematical computation, input/output processing, memory management, and input/output. Application programming interface (API) Header files The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Null-terminated String
In computer programming, a null-terminated string is a character string stored as an array containing the characters and terminated with a ''null character'' (a character with an internal value of zero, called "NUL" in this article, not same as the glyph zero). Alternative names are '' C string'', which refers to the C programming language and ASCIIZ (although C can use encodings other than ASCII). The length of a string is found by searching for the (first) NUL. This can be slow as it takes O(''n'') (linear time) with respect to the string length. It also means that a string cannot contain a NUL (there is a NUL in memory, but it is after the last character, not the string). History Null-terminated strings were produced by the .ASCIZ directive of the PDP-11 assembly languages and the ASCIZ directive of the MACRO-10 macro assembly language for the PDP-10. These predate the development of the C programming language, but other forms of strings were often used. At the time C ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C11 (C Standard Revision)
C11 (previously C1X, formally ISO/IEC 9899:2011) is a past standard for the C programming language. It replaced C99 (standard ISO/IEC 9899:1999) and has been superseded by C17 (standard ISO/IEC 9899:2018). 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. The final draft, N1570, was published in April 2011. The new standard passed its final draft review on October 10, 2011 and was officially ratified by ISO and published as ISO/IEC 9899:2011 on December 8, 2011, with no comments requiring resolution by participating national bodies. A standard macro __STDC_VERSION__ is defined with value 201112L to indicate that C11 support is available. Changes from C99 The standard includes several changes to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable-width Encoding
A variable-width encoding is a type of character encoding scheme in which codes of differing lengths are used to encode a character set (a repertoire of symbols) for representation, usually in a computer. Most common variable-width encodings are multibyte encodings (aka MBCS – multi-byte character set), which use varying numbers of bytes (octets) to encode different characters. (Some authors, notably in Microsoft documentation, use the term ''multibyte character set,'' which is a misnomer, because representation size is an attribute of the encoding, not of the character set.) Early variable-width encodings using less than a byte per character were sometimes used to pack English text into fewer bytes in adventure games for early microcomputers. However disks (which unlike tapes allowed random access allowing text to be loaded on demand), increases in computer memory and general purpose compression algorithms have rendered such tricks largely obsolete. Multibyte encodings are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shift JIS
Shift JIS (also SJIS, MIME name Shift_JIS, known as PCK in Solaris contexts) is a character encoding for the Japanese language, originally developed by the Japanese company ASCII Corporation in conjunction with Microsoft and standardized as JIS X 0208 Appendix 1. Shift JIS is based on character sets defined within JIS standards (for the single-byte characters) and (for the double-byte characters). , less than 0.05% of surveyed web pages used Shift JIS (actually decoded as its superset Windows-31J encoding), a decline from 1.3% in July 2014. Shift JIS is the third-most declared character encoding for Japanese websites (though in effect it means its superset Windows-31J is used, so it is third-most popular), declared by 1.0% of sites in the .jp domain, while UTF-8 is used by 99% of Japanese websites. Shift JIS is also sometimes used in QR codes (they are a Japanese invention also allowing UTF-8, which may though be preferred use). Structure Shift JIS is an extension ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C++20
C20 or C-20 may refer to: Science and technology * Carbon-20 (C-20 or 20C), an isotope of carbon * C20, the smallest possible fullerene (a carbon molecule) * C20 (engineering), a mix of concrete that has a compressive strength of 20 newtons per square millimeter * Malignant neoplasm of rectum, a type of colorectal cancer (ICD-10 code: C20) * Caldwell 20 or North America Nebula, an emission nebula in the constellation Cygnus * IEC 60320 C20, a polarised, three pole socket electrical connector * C20 (Capacity, 20 hours), C100 (100 hours), battery capacity Transportation and military * Colt Canada C20 DMR, a Canadian designated marksman rifle * , a 1910 British C-class submarine * Sauber C20, a 2001 racing car * SL C20, a type of rolling stock used in the Stockholm metro * , a cruiser of the Royal Navy * C-20, the proposed in-service designation of the Fokker F-32 * C-20A/B/C/D/E, variants of the Gulfstream III * C-20F/G/H/J, variants of the Gulfstream IV * C20 is a version of the Alli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C23 (C Standard Revision)
C23, formally ISO/IEC 9899:2024, is the current open standard for the C programming language, which supersedes C17 (standard ISO/IEC 9899:2018). It was started in 2016 informally as C2x, and was published on October 31, 2024. The freely available draft most similar to the one published is document N3220 (see Available texts, below). The first WG14 meeting for the C2x draft was held in October 2019, virtual remote meetings were held in 2020 due to the COVID-19 pandemic, then various teleconference meetings continued to occur through 2024. In C23, the value of __STDC_VERSION__ changes from 201710L to 202311L. The common names "C17" and "C23" reflect these values, which are frozen prior to final adoption, rather than the years in the ISO standards identifiers (9899:2018 and 9899:2024). Features Changes integrated into the latest working draft of C23 are listed below. Standard Library New functions * Add memset_explicit() function in to erase sensitive data, where memory stor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language)
C (''pronounced'' '' – like the letter c'') is a general-purpose programming language. It was created in the 1970s by Dennis Ritchie and remains very widely used and influential. By design, C's features cleanly reflect the capabilities of the targeted Central processing unit, CPUs. It has found lasting use in operating systems code (especially in Kernel (operating system), kernels), device drivers, and protocol stacks, but its use in application software has been decreasing. C is commonly used on computer architectures that range from the largest supercomputers to the smallest microcontrollers and embedded systems. A successor to the programming language B (programming language), B, C was originally developed at Bell Labs by Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the most widely used programming langu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Const-correctness
In some programming languages, const is a type qualifier (a keyword applied to a data type) that indicates that the data is read-only. While this can be used to declare constants, in the C family of languages differs from similar constructs in other languages in that it is part of the ''type'', and thus has complicated behavior when combined with pointers, references, composite data types, and type-checking. In other languages, the data is not in a single memory location, but copied at compile time for each use. Languages which use it include C, C++, D, JavaScript, Julia, and Rust. Introduction When applied in an object declaration, it indicates that the object is a constant: its value may not be changed, unlike a variable. This basic use – to declare constants – has parallels in many other languages. However, unlike in other languages, in the C family of languages the const is part of the ''type'', not part of the ''object''. For example, in C, declar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UTF-32
UTF-32 (32- bit Unicode Transformation Format), sometimes called UCS-4, 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. The main advantage of UTF-32 is that the Unicode code points are directly indexed. Finding the ''Nth'' code point in a sequence of code points is a constant-time operation. In contrast, a variable-length code requires linear-time to count ''N'' code points from the start of the string. This makes UTF-32 a simple replacement in code that uses integers that are incremented by one to examine each location in a string, as was commonly done for ASCII. However, Unicode code ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
