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C POSIX Library
The C POSIX library is a specification of a C standard library for POSIX systems. It was developed at the same time as the ANSI C standard. Some effort was made to make POSIX compatible with standard C; POSIX includes additional functions to those introduced in standard C. On the other hand, the 5 headers that were added to the C standard library with C11, were not likewise included in subsequent revisions of POSIX. It may be included in any C++ project, however the C++ standard library may have its own implementation of certain features, such as rather than , rather than , or rather than . C POSIX library header files See also * POSIX * C standard library * C++ standard library The C standard library, sometimes referred to as libc, is the standard library for the C programming language, as specified in the ISO C standard.ISO/ IEC (2018). '' ISO/IEC 9899:2018(E): Programming Languages - C §7'' Starting from the origina ... References Official List of headers in the ... [...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] |
File Locking
File locking is a mechanism that restricts access to a computer file, or to a region of a file, by allowing only one user or process to modify or delete it at a specific time, and preventing reading of the file while it's being modified or deleted. Systems implement locking to prevent an ''interceding update'' scenario, which is an example of a race condition, by enforcing the serialization of update processes to any given file. The following example illustrates the interceding update problem: # Process A reads a customer record from a file containing account information, including the customer's account balance and phone number. # Process B now reads the same record from the same file, so it has its own copy. # Process A changes the account balance in its copy of the customer record and writes the record back to the file. # Process B, which still has the original ''stale'' value for the account balance in its copy of the customer record, updates the account balance and writes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
POSIX Threads
In computing, POSIX Threads, commonly known as pthreads, is an execution model that exists independently from a programming language, as well as a parallel execution model. It allows a program to control multiple different flows of work that overlap in time. Each flow of work is referred to as a '' thread'', and creation and control over these flows is achieved by making calls to the POSIX Threads API. POSIX Threads is an API defined by the Institute of Electrical and Electronics Engineers (IEEE) standard ''POSIX.1c, Threads extensions (IEEE Std 1003.1c-1995)''. Implementations of the API are available on many Unix-like POSIX-conformant operating systems such as FreeBSD, NetBSD, OpenBSD, Linux, macOS, Android, Solaris, Redox, and AUTOSAR Adaptive, typically bundled as a library libpthread. DR-DOS and Microsoft Windows implementations also exist: within the SFU/SUA subsystem which provides a native implementation of a number of POSIX APIs, and also within third-party package ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Control Protocol
The Transmission Control Protocol (TCP) is one of the main communications protocol, protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliability (computer networking), reliable, ordered, and error detection and correction, error-checked delivery of a reliable byte stream, stream of octet (computing), octets (bytes) between applications running on hosts communicating via an IP network. Major internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP, which is part of the transport layer of the TCP/IP suite. Transport Layer Security, SSL/TLS often runs on top of TCP. TCP is Connection-oriented communication, connection-oriented, meaning that sender and receiver firstly need to establish a connection based on agreed parameters; they do this through three-way Ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Message Queue
In computer science, message queues and mailboxes are software-engineering components typically used for inter-process communication (IPC), or for inter- thread communication within the same process. They use a queue for messaging – the passing of control or of content. Group communication systems provide similar kinds of functionality. The message queue paradigm is a sibling of the publisher/subscriber pattern, and is typically one part of a larger message-oriented middleware system. Most messaging systems support both the publisher/subscriber and message queue models in their API, e.g. Java Message Service (JMS). Competing Consumers pattern enables multiple concurrent consumers to process messages on the same message queue. Remit and ownership Message queues implement an asynchronous communication pattern between two or more processes/threads whereby the sending and receiving party do not need to interact with the message queue at the same time. Messages placed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Localization Functions
In computing, C localization functions are a group of functions in the C programming language implementing basic localization routines. The functions are used in multilingual programs to adapt to the specific locale. In particular, the way of displaying of numbers and currency can be modified. These settings affect the behaviour of input/output functions in the C Standard Library. Overview of functions C localization functions and types are defined in ( header in C++). Criticism C standard localization functions are criticized because the localization state is stored globally. This means that in a given program all operations involving a locale can use only one locale at a time. As a result, it is very difficult to implement programs that use more than one locale. The functions alter the behavior of printf/scanf/strtod which are often used to write saved data to a file or to other programs. The result is that a saved file in one locale will not be readable in another local ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Alternative Tokens
C alternative tokens refer to a set of alternative spellings of common operators in the C programming language. They are implemented as a group of macro constants in the C standard library in the iso646.h header. The tokens were created by Bjarne Stroustrup for the pre-standard C++ language and were added to the C standard in a 1995 amendment to the C90 standard via library to avoid the breakage of existing code. The alternative tokens allow programmers to use C language bitwise and logical operators which could otherwise be hard to type on some international and non-QWERTY keyboards. The name of the header file they are implemented in refers to the ISO/IEC 646 standard, a 7-bit character set with a number of regional variations, some of which have accented characters in place of the punctuation marks used by C operators. The macros The iso646.h header defines the following 11 macros as stated below: C++ The above-mentioned identifiers are operator keywords in the ISO C+ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Character Encoding
Character encoding is the process of assigning numbers to graphical character (computing), characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using computers. The numerical values that make up a character encoding are known as code points and collectively comprise a code space or a code page. Early character encodings that originated with optical or electrical telegraphy and in early computers could only represent a subset of the characters used in written languages, sometimes restricted to Letter case, upper case letters, Numeral system, numerals and some punctuation only. Over time, character encodings capable of representing more characters were created, such as ASCII, the ISO/IEC 8859 encodings, various computer vendor encodings, and Unicode encodings such as UTF-8 and UTF-16. The Popularity of text encodings, most popular character encoding on the World Wide Web is UTF-8, which is used in 98.2% of surve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iconv
In Unix and Unix-like operating systems, iconv (an abbreviation of internationalization conversion) is a command-line program and a standardized application programming interface (API) used to convert between different character encodings. "It can convert from any of these encodings to any other, through Unicode conversion." History Initially appearing on the HP-UX operating system,iconv() as well as the utility was standardized within XPG4 and is part of the Single UNIX Specification (SUS). Implementations Most Linux distributions provide an implementation, either from the GNU Standard C Library (included since version 2.1, February 1999), or the more traditional GNU libiconv, for systems based on other Standard C Libraries. The iconv function on both is licensed as LGPL, so it is linkable with closed source applications. Unlike the libraries, the iconv utility is licensed under GPL in both implementations. The GNU libiconv implementation is portable, and can be used o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group Identifier (Unix)
In Unix-like systems, multiple users can be put into '' groups''. POSIX and conventional Unix file system permissions are organized into three classes, ''user'', ''group'', and ''others''. The use of groups allows additional abilities to be delegated in an organized fashion, such as access to disks, printers, and other peripherals. This method, among others, also enables the superuser to delegate some administrative tasks to normal users, similar to the ''Administrators'' group on Microsoft Windows NT and its derivatives. A group identifier, often abbreviated to GID, is a numeric value used to represent a specific group. The range of values for a GID varies amongst different systems; at the very least, a GID can be between 0 and 32,767, with one restriction: the login group for the superuser must have GID 0. This numeric value is used to refer to groups in the /etc/passwd and /etc/group files or their equivalents. Shadow password files and Network Information Service also refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glob (programming)
glob() () is a libc function for ''globbing'', which is the archetypal use of pattern matching against the names in a filesystem directory such that a name pattern is expanded into a list of names matching that pattern. Although ''globbing'' may now refer to glob()-style pattern matching of any string, not just expansion into a list of filesystem names, the original meaning of the term is still widespread. The glob() function and the underlying gmatch() function originated at Bell Labs in the early 1970s alongside the original AT&T UNIX itself and had a formative influence on the syntax of UNIX command line utilities and therefore also on the present-day reimplementations thereof. In their original form, glob() and gmatch() derived from code used in Bell Labs in-house utilities that developed alongside the original Unix in the early 1970s. Among those utilities were also two command line tools called glob and find; each could be used to pass a list of matching filenames to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
