ensure-directories-exist pathspec &key verbose => pathspec, created
Arguments and Values:
pathspec---a pathname designator.
verbose---a generalized boolean.
created---a generalized boolean.
Tests whether the directories containing the specified file actually exist, and attempts to create them if they do not.
If the containing directories do not exist and if verbose is true, then the implementation is permitted (but not required) to perform output to standard output saying what directories were created. If the containing directories exist, or if verbose is false, this function performs no output.
The primary value is the given pathspec so that this operation can be straightforwardly composed with other file manipulation expressions. The secondary value, created, is true if any directories were created.
The host computer's file system.
An error of type file-error is signaled if the host, device, or directory part of pathspec is wild.
If the directory creation attempt is not successful, an error of type file-error is signaled; if this occurs, it might be the case that none, some, or all of the requested creations have actually occurred within the file system.
probe-file, open, Section 19.1.2 (Pathnames as Filenames)