The prefix is a path concept that is used to handle:
- root directories on UNIX platforms,
- drive specifiers, root directories, and UNC pathnames on Microsoft Windows platforms
Prefix can be:
|A disk-drive specifier||C:\|
|A UNIX root directory||“/”|
|A Microsoft Windows UNC pathname||\\\\|
For UNIX platforms:
- the prefix of an absolute pathname is always /.
- Relative pathnames have no prefix.
- The abstract pathname denoting the root directory has the prefix “/” and an empty name sequence.
For Microsoft Windows platforms:
- the prefix of a pathname that contains a drive specifier consists of the drive letter followed by “:” and possibly followed by “\\” if the pathname is absolute.
- the prefix of a UNC pathname (network shares) is “\\\\”; the hostname and the share name are the first two names in the name sequence.
- A relative pathname that does not specify a drive has no prefix.