ToC DocOverview CGDoc RelNotes Index PermutedIndex
Allegro CL
Home Previous Up Next Table of Contents Index
  19 Filenames   19.2 Pathnames   19.2.2 Interpreting Pathname Component Values   19.2.2.2 Special Pathname Component Values

19.2.2.2.3 :UNSPECIFIC as a Component Value

If :unspecific is the value of a pathname component, the component is considered to be "absent" or to "have no meaning" in the filename being represented by the pathname.

Whether a value of :unspecific is permitted for any component on any given file system accessible to the implementation is implementation-defined. A conforming program must never unconditionally use a :unspecific as the value of a pathname component because such a value is not guaranteed to be permissible in all implementations. However, a conforming program can, if it is careful, successfully manipulate user-supplied data which contains or refers to non-portable pathname components. And certainly a conforming program should be prepared for the possibility that any components of a pathname could be :unspecific.

When reading1 the value of any pathname component, conforming programs should be prepared for the value to be :unspecific.

When writing1 the value of any pathname component, the consequences are undefined if :unspecific is given for a pathname in a file system for which it does not make sense.

19.2.2.2.3.1  Relation between component values NIL and :UNSPECIFIC


Home Previous Up Next Table of Contents Index
© Franz Inc. 1998-2017 - File last updated 01-11-2017