READDIR(2) READDIR(2)
NAME
readdir - read directory and sort files
SYNOPSIS
include "readdir.m";
readdir := load Readdir Readdir->PATH;
NAME, ATIME, MTIME, SIZE, NONE: con iota;
COMPACT: con (1<<4);
DESCENDING: con (1<<5);
init: fn(path: string, sortkey: int): (array of ref Sys->Dir, int);
readall: fn(fd: ref Sys->FD, sortkey: int): (array of ref Sys->Dir, int);
sortdir: fn(a: array of ref Sys->Dir, key: int): (array of ref Sys->Dir, int);
DESCRIPTION
Readdir provides functions to read and sort the contents of
a directory. Each function returns its result as a tuple
that represents the directory contents as an array of refer-
ences to Sys->Dir values, one per file (see sys-stat(2) for
a description of Dir). The integer element of the tuple is
the number of entries returned, or -1 if there was an error
reading the directory. Readdir differs from sys-dirread(2)
in returning the contents of the whole directory, not just a
chunk of it, and in allowing the result to be sorted.
Init is most often used: it reads the contents of the direc-
tory path and sorts the resulting array according to
sortkey.
The sorting criteria for the returned array are based on
sortkey as follows:
NAME Sort files alphabetically by name.
ATIME Sort files by access time, most recently accessed
first.
MTIME Sort files by modification time, most recently modi-
fied first.
SIZE Sort files by size, largest file first.
NONE Files are left in directory order, unsorted.
If the value DESCENDING is or'd into any of the values
above, except NONE, the order of sorting is reversed.
The sort used is stable, of particular importance in the
presence of duplicate names in a union mount. If the value
COMPACT is or'd into any of the values above, including
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READDIR(2) READDIR(2)
NONE, only the first (outermost) entry with a given name
will be returned from reading a union mount, if names are
duplicated in the union.
Readall reads file descriptor fd which must be open on a
directory, and returns the contents after applying sortkey
as described above for init.
Sortdir sorts the array a according to the given key, as
defined earlier, except that the COMPACT option has no
effect.
SOURCE
/appl/lib/readdir.b
SEE ALSO
sys-dirread(2)
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