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C is a general-purpose, imperative computer programming language, supporting structured programming, lexical variable scope and recursion, while a static type system prevents many unintended operations. By design, C provides constructs that map efficiently to typical machine instructions, and therefore it has found lasting use in applications that had formerly been coded in assembly language, including operating systems, as well as various application software for computers ranging from supercomputers to embedded systems.

Despite its low-level capabilities, the language was designed to encourage cross-platform programming. A standards-compliant and portably written C program can be compiled for a very wide variety of computer platforms and operating systems with few changes to its source code. The language has become available on a very wide range of platforms, from embedded microcontrollers to supercomputers.

C was originally developed by Dennis Ritchie between 1969 and 1973 at Bell Labs and used to re-implement the Unix operating systems. It has since become one of the most widely used programming languages of all time, with C compilers from various vendors available for the majority of existing computer architectures and operating systems.

Common Compilers

The process to compile a C program differs between compilers and operating systems. Most operating systems ship without a compiler, so you will have to install one. Some common compilers choices are:

The following documents should give you a good overview on how to get started using a few of the most common compilers:

Compiler C version Support

Note that compilers have varying levels of support for standard C with many still not completely supporting C99. For example, as of the 2015 release, MSVC supports much of C99 yet still has some important exceptions for support of the language itself (e.g the preprocessing seems non-conformant) and for the C library (e.g. <tgmath.h>), nor do they necessarily document their “implementation dependent choices”. Wikipedia has a table showing support offered by some popular compilers.

Some compilers (notably GCC) have offered, or continue to offer, compiler extensions that implement additional features that the compiler producers deem necessary, helpful or believe may become part of a future C version, but that are not currently part of any C standard. As these extensions are compiler specific they can be considered to not be cross-compatible and compiler developers may remove or alter them in later compiler versions. The use of such extensions can generally be controlled by compiler flags.

Additionally, many developers have compilers that support only specific versions of C imposed by the environment or platform they are targeting.

If selecting a compiler, it is recommended to choose a compiler that has the best support for the latest version of C allowed for the target environment.

Code style (off-topic here):