Various versions of C language

GCC specifies options for different versions of the C language:

GNU (modified version of GNU for C89): default,-std=gnu89

ANSI, ISO C90:-ansi,-std=c89 (ANSI C (C89) and ISO C (C90) content basically the same, mainly format organization is not the same)

ISO C99:-std=c99

GNU (modified version of C99 by GNU):-std=gnu99

The C language was introduced in the early 1870s, and in 1978 the American Telephone and Telegraph Company (T) Bell Laboratory officially released the C language, followed by the National Bureau of Standards (American Nation standards Institute, ANSI) developed a set of C language standards, published in 1983, commonly referred to as ANSI C.

The father of C language--Ricky

Before we learn the C language, let's look at the history of C language first.

C language is a universal, modular, programmatic programming language, is widely used in operating systems and application software development. Due to its high efficiency and portability, it is favored by developers to adapt to different hardware and software platforms.

Early development of C language

The initial development of the C language began in 1969-1973 at Bell Labs at the American Telephone and Telegraph Corporation (t). According to the C language inventor Dennis Ritchie (Dennis Ritchie), the most important period of research and development in C language is in 1972 years.

Description: Dennis Ritchie (Dennis Ritchie), father of C language, father of Unix. 1978 with Blaine Cornigan (Brian Kernighan) published the famous "C programming language (the C programming Language)", now the book has been translated into multiple languages, the C language is one of the most authoritative teaching materials. October 12, 2011 (Beijing time is October 13), Dennis Ritchie died at the age of 70.

C was named C because the C language originated from the B language invented by Ken Thompson, whereas the B language originated in the Bcpl language.

The birth of C language and the development of UNIX operating system is inseparable, the original Unix operating system is written in assembly language, 1973 UNIX operating system core in C language rewrite, since then, C language has become the main language to write the operating system.

K&r C

In 1978, Dennis Ritchie (Dennis Ritchie) and Blaine Cornigan (Brian Kernighan) published a book called "The C Programming Language" (the Chinese name is "C programming language"). The book is called "K&r" by C-language developers and has been used for many years as an unofficial standard for C. People call this version of the C language "K&r C".

In 1988 Dennis Ritchie (Dennis Ritchie) and Blaine Cornigan (Brian Kernighan) revised the book, published the second edition of the C programming Language, and the second edition covered the ANSI C language standard. The second edition has since become the university computer education about C language Classics textbook, many years later also did not appear the better version.

ANSI C and ISO C

In the 1970-80 's, C language was widely used, from mainframe to small microcomputer, also derived from the C language of many different versions.

In order to unify the C language version, a committee was set up in 1983 by the National Bureau of Standards (American Nation Standards Institute, abbreviated as ANSI) to develop the C language standard. The 1989 C language standard was approved, known as ANSI x3.159-1989 "programming Language C". This version of the C language standard is commonly referred to as ANSI C. And since this version was released in 89, it is also known as C89.

Later, ANSI submitted this standard to ISO (International Standards Organization), which was adopted by ISO in 1990 as an international standard, called ISO C. And because this version was released in 1990, it is also known as C90.

ANSI C (C89) is basically the same as the ISO C (C90) content, mainly the format organization is different.

Because ANSI and ISO C standard content is basically the same, so for the C standard, can be called ANSI C, also can be said to be ISO C, or Ansi/iso C.

Note: In the future you will see ANSI C, ISO C, C89, C90, to know that the content of these standards are the same.

Currently, almost all development tools support the Ansi/iso C standard. Is the most widely used standard version of C language.

C99

After the ANSI C standard was established, the C language specification did not change much over a long period of time. In 1995, the C programming language Working group revised the C language to become the ISO/IEC 9,899:1999 standard, which was released in 1999, and is often C99.

But each company's support for C99 has shown a different interest. When GCC and some other commercial compilers supported most of C99 's features, Microsoft and Borland seemed uninterested.

Description: GCC (GNU Compiler Collection,gnu Compiler Collection) is a set of compilers developed by the GNU project that support multiple programming languages.

To sum up, the current widely used C language version is Ansi/iso C, the most classic C language teaching material is "C programming language (the C programming Language)".

Source: http://see.xidian.edu.cn/cpp/html/1.html

Various versions of C language