The Python interpreter and the extensive standard library are freely availablein source or binary form for all major platforms from the Python web site, , and may be freely distributed. The same site alsocontains distributions of and pointers to many free third party Python modules,programs and tools, and additional documentation.
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While The Python Language Reference describes the exact syntax andsemantics of the Python language, this library reference manualdescribes the standard library that is distributed with Python. It alsodescribes some of the optional components that are commonly includedin Python distributions.
The Python installers for the Windows platform usually includethe entire standard library and often also include many additionalcomponents. For Unix-like operating systems Python is normally providedas a collection of packages, so it may be necessary to use the packagingtools provided with the operating system to obtain some or all of theoptional components.
In addition to the standard library, there is an active collection ofhundreds of thousands of components (from individual programs and modules topackages and entire application development frameworks), available fromthe Python Package Index.
The Arduino environment can be extended through the use of libraries, just like most programming platforms. Libraries provide extra functionality for use in sketches, e.g. working with hardware or manipulating data. To use a library in a sketch, select it from Sketch > Import Library. A number of libraries come installed with the IDE, but you can also download or create your own. See these instructions for details on installing libraries. There is also a tutorial on writing your own libraries. See the API Style Guide for information on making a good Arduino-style API for your library.
This section of the documentation contains reference content for the Microsoft implementation of the ISO standard C and C++ languages. The language reference includes documentation for the preprocessor, compiler intrinsics, and supported assembly languages.
This is a reference document for nvcc, the CUDA compiler driver. nvcc accepts a range of conventional compiler options, such as for defining macros and include/library paths, and for steering the compilation process.
The C standard library or libc is the standard library for the C programming language, as specified in the ISO C standard.[1] Starting from the original ANSI C standard, it was developed at the same time as the C library POSIX specification, which is a superset of it.[2][3] Since ANSI C was adopted by the International Organization for Standardization,[4] the C standard library is also called the ISO C library.
The C standard library provides macros, type definitions and functions for tasks such as string handling, mathematical computations, input/output processing, memory management, and several other operating system services.
The application programming interface (API) of the C standard library is declared in a number of header files. Each header file contains one or more function declarations, data type definitions, and macros.
On Unix-like systems, the authoritative documentation of the actually implemented API is provided in the form of man pages. On most systems, man pages on standard library functions are in section 3; section 7 may contain some more generic pages on underlying concepts (e.g. man 7 math_error in Linux).
Unix-like systems typically have a C library in shared library form, but the header files (and compiler toolchain) may be absent from an installation so C development may not be possible. The C library is considered part of the operating system on Unix-like systems. The C functions, including the ISO C standard ones, are widely used by programs, and are regarded as if they were not only an implementation of something in the C language, but also de facto part of the operating system interface. Unix-like operating systems generally cannot function if the C library is erased. This is true for applications which are dynamically as opposed to statically linked. Further, the kernel itself (at least in the case of Linux) operates independently of any libraries.
On Microsoft Windows, the core system dynamic libraries (DLLs) provide an implementation of the C standard library for the Microsoft Visual C++ compiler v6.0; the C standard library for newer versions of the Microsoft Visual C++ compiler is provided by each compiler individually, as well as redistributable packages. Compiled applications written in C are either statically linked with a C library, or linked to a dynamic version of the library that is shipped with these applications, rather than relied upon to be present on the targeted systems. Functions in a compiler's C library are not regarded as interfaces to Microsoft Windows.
Some compilers (for example, GCC[7]) provide built-in versions of many of the functions in the C standard library; that is, the implementations of the functions are written into the compiled object file, and the program calls the built-in versions instead of the functions in the C library shared object file. This reduces function-call overhead, especially if function calls are replaced with inline variants, and allows other forms of optimization (as the compiler knows the control-flow characteristics of the built-in variants), but may cause confusion when debugging (for example, the built-in versions cannot be replaced with instrumented variants).
Some functions in the C standard library have been notorious for having buffer overflow vulnerabilities and generally encouraging buggy programming ever since their adoption.[a] The most criticized items are:
Except the extreme case with gets(), all the security vulnerabilities can be avoided by introducing auxiliary code to perform memory management, bounds checking, input checking, etc. This is often done in the form of wrappers that make standard library functions safer and easier to use. This dates back to as early as The Practice of Programming book by B. Kernighan and R. Pike where the authors commonly use wrappers that print error messages and quit the program if an error occurs.
The ISO C committee published Technical reports TR 24731-1[12] and is working on TR 24731-2[13] to propose adoption of some functions with bounds checking and automatic buffer allocation, correspondingly. The former has met severe criticism with some praise,[14][15] the latter received mixed responses. Despite this, TR 24731-1 has been implemented into Microsoft's C standard library and its compiler issues warnings when using old "insecure" functions.
The error handling of the functions in the C standard library is not consistent and sometimes confusing. According to the Linux manual page math_error, "The current (version 2.8) situation under glibc is messy. Most (but not all) functions raise exceptions on errors. Some also set errno. A few functions set errno, but don't raise an exception. A very few functions do neither."[16]
Both Unix and C were created at AT&T's Bell Laboratories in the late 1960s and early 1970s. During the 1970s the C language became increasingly popular. Many universities and organizations began creating their own variants of the language for their own projects. By the beginning of the 1980s compatibility problems between the various C implementations became apparent. In 1983 the American National Standards Institute (ANSI) formed a committee to establish a standard specification of C known as "ANSI C". This work culminated in the creation of the so-called C89 standard in 1989. Part of the resulting standard was a set of software libraries called the ANSI C standard library.
POSIX, as well as SUS, specify a number of routines that should be available over and above those in the basic C standard library. The POSIX specification includes header files for, among other uses, multi-threading, networking, and regular expressions. These are often implemented alongside the C standard library functionality, with varying degrees of closeness. For example, glibc implements functions such as fork within libc.so, but before NPTL was merged into glibc it constituted a separate library with its own linker flag argument. Often, this POSIX-specified functionality will be regarded as part of the library; the basic C library may be identified as the ANSI or ISO C library.
BSD libc is a superset of the POSIX standard library supported by the C libraries included with BSD operating systems such as FreeBSD, NetBSD, OpenBSD and macOS. BSD libc has some extensions that are not defined in the original standard, many of which first appeared in 1994's 4.4BSD release (the first to be largely developed after the first standard was issued in 1989). Some of the extensions of BSD libc are:
Some languages include the functionality of the standard C library in their own libraries. The library may be adapted to better suit the language's structure, but the operational semantics are kept similar. The C++ language, for example, includes the functionality of the C standard library in the namespace std (e.g., std::printf, std::atoi, std::feof), in header files with similar names to the C ones (cstdio, cmath, cstdlib, etc.). Other languages that take similar approaches are D, Perl, Ruby and the main implementation of Python known as CPython. In Python 2, for example, the built-in file objects are defined as "implemented using C's stdio package",[38] so that the available operations (open, read, write, etc.) are expected to have the same behavior as the corresponding C functions. Rust has a crate called libc which allows several C functions, structs, and other type definitions to be used.[39]
The C standard library is small compared to the standard libraries of some other languages. The C library provides a basic set of mathematical functions, string manipulation, type conversions, and file and console-based I/O. It does not include a standard set of "container types" like the C++ Standard Template Library, let alone the complete graphical user interface (GUI) toolkits, networking tools, and profusion of other functionality that Java and the .NET Framework provide as standard. The main advantage of the small standard library is that providing a working ISO C environment is much easier than it is with other languages, and consequently porting C to a new platform is comparatively easy. 2ff7e9595c
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