Isabs

Isabs is a term used in programming to denote a function that checks whether a given filesystem path is absolute. Typically, it accepts a single argument, a string representing a path, and returns a boolean value: true if the path is absolute, false otherwise.

The exact rules for what constitutes an absolute path depend on the operating system and the library implementing the function. On Unix-like systems, an absolute path usually begins with a forward slash, such as /usr/bin. On Windows, an absolute path typically starts with a drive letter and colon (for example C:\Program Files) or with a UNC prefix (\\server\share). Different languages may implement these rules with slight variations, but the general idea is to distinguish paths that specify a root from those that are relative to some base directory.

In practice, isabs is typically a syntactic check rather than a filesystem query. It does not verify that the path exists, nor does it resolve symbolic links or relative components like .. or . beyond determining whether the path has an absolute form. Some edge cases can differ across implementations, such as how tilde (~) expansions are handled.

Many languages provide a function with similar intent under different names. For example, Python offers os.path.isabs, Java has Path.isAbsolute(), and Node.js exposes path.isAbsolute(). The specific behavior of isabs can vary by language and version, so consulting the respective documentation is recommended for precise semantics.