.3 File Extension

Origin Of This File.

The concept of man pages dates back to the early development of Unix in the 1970s at AT&T’s Bell Labs. The original Unix operating system was designed to be highly modular and extensible, which necessitated a robust system of documentation.

The manual pages were created to provide detailed, accessible documentation on various system components, commands, and programming interfaces. Section 3 of these manual pages specifically focuses on the C standard library functions and system calls.

The .3 extension is a convention used by Unix systems to indicate that a manual page belongs to this particular section.

The practice of using numbered sections helps organize the documentation into different categories, making it easier for users to locate information.

File Structure Technical Specification.

The .3 file extension is associated with man pages that are formatted using the troff/groff formatting system, though modern systems may use other formats such as nroff. The typical structure of a Section 3 manual page includes several key sections:

1. Name: The name of the function or library being described, along with a brief description of its purpose.
2. Synopsis: The function’s prototype, including its parameters and return value.
3. Description: A detailed explanation of what the function does, including its behavior, any special considerations, and how it interacts with other system components.
4. Return Value: Information on what the function returns and under what conditions.
5. Errors: Descriptions of any errors or exceptions that the function might generate.
6. See Also: References to related functions or documentation.
7. Notes: Any additional information that might be useful for understanding the function or its use.

The technical specification of these files involves using troff/groff macros to format the content. These macros define how different sections of the page should be rendered, including headings, bullet points, and code formatting.