shithub: purgatorio

ref: 1dbb193077af7ba6ff7fb70a4dd465480764382e
dir: /man/2/readdir/

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.TH READDIR 2
.SH NAME
readdir \- read directory and sort files
.SH SYNOPSIS
.EX
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);
.EE
.SH DESCRIPTION
.B 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 references to
.B Sys->Dir
values, one per file
(see
.IR sys-stat (2)
for a description of
.BR Dir ).
The integer element of the tuple is the number of entries
returned, or \-1 if there was an error reading the directory.
.B Readdir
differs from
.I 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.
.PP
.B Init
is most often used: it
reads the contents of the directory
.I path
and sorts the resulting array according to
.IR sortkey .
.PP
The sorting criteria for the returned array are based on
.I sortkey
as follows:
.PP
.TF MTIME
.PD
.TP
.B NAME
Sort files alphabetically by name.
.TP
.B ATIME
Sort files by access time, most recently accessed first.
.TP
.B MTIME
Sort files by modification time, most recently modified first.
.TP
.B SIZE
Sort files by size, largest file first.
.TP
.B NONE
Files are left in directory order, unsorted.
.PP
If the value
.B DESCENDING
is or'd into any of the values above, except
.BR NONE ,
the order of sorting is reversed.
.PP
The sort used is stable, of particular importance in the presence of
duplicate names in a union mount.
If the value
.B COMPACT
is or'd into any of the values above, including
.BR 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.
.PP
.B Readall
reads file descriptor
.I fd
which must be open on a directory,
and returns the contents after applying
.I sortkey
as described above for
.BR init .
.PP
.B Sortdir
sorts the array
.I a
according to the given
.IR key ,
as defined earlier, except that
the
.B COMPACT
option has no effect.
.SH SOURCE
.B /appl/lib/readdir.b
.SH SEE ALSO
.IR sys-dirread (2)