definition of filename?

Question

After years of programming it's still some of the simple things that keep tripping me up.

Is there a commonly agreed definition of filename ?

Even the wikipedia article confuses the two interpretations.

It starts by defining it as 'a special kind of string used to uniquely identify a file stored on the file system of a computer'. That seems clear enough, and suggests that a filename is a fully qualified filename, specifying the complete path to the file.

However, it then goes on to:

• talk about basename and extension (so basename would contain an absolute path ?)
• says that the length of a filename in DOS is limited to 8.3
• says that a filename without a path part is assumed to be a file in the current working directory (so the filename does not uniquely identify a file)

So, simple questions:

• what is a correct definition of 'filename' (include references)
• how should I unambiguously name variables for:
  • a path to a file (which can be absolute/full or relative)
  • a path to a resource that can be a file/directory/socket

Answer 1

No references, just vernacular from experience. When I'm being specific I tend to use:

path or filespec (or file specification): all of the characters needed to identify a file on a filesystem. The path may be absolute (starting from the root, or topmost, directory) or relative (starting from the currently active directory).

filename: the characters needed to identify a file within the current directory.

extension: characters at the end of the filename that typically identify the type of the file. By convention, the extension usually starts with a dot ("."), and a filename may contain more than one extension.

basename: the filename up to (but not including) the dot that begins the first extension.