man2/readdir.2

   1 .\" Copyright (C) 1995 Andries Brouwer (aeb@cwi.nl)
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  22 .\"
  23 .\" Written 11 June 1995 by Andries Brouwer <aeb@cwi.nl>
  24 .\" Modified 22 July 1995 by Michael Chastain <mec@duracef.shout.net>:
  25 .\"   In 1.3.X, returns only one entry each time; return value is different.
  26 .\" Modified 2004-12-01, mtk, fixed headers listed in SYNOPSIS
  27 .\"
  28 .TH READDIR 2  1995-07-22 "Linux 1.3.6" "Linux Programmer's Manual"
  29 .SH NAME
  30 readdir \- read directory entry
  31 .SH SYNOPSIS
  32 .nf
  33 .B #include <linux/types.h>
  34 .B #include <linux/dirent.h>
  35 .B #include <linux/unistd.h>
  36 .B #include <errno.h>
  37 .sp
  38 .B _syscall3(int, readdir, unsigned int, fd, struct dirent *, dirp,
  39 .B "          unsigned int, count)"
  40           /* Using \fBsyscall\fP(2) may be preferable; see \fBintro\fP(2) */
  41 .sp
  42 .BI "int readdir(unsigned int " fd ", struct dirent *" dirp ","
  43 .BI "            unsigned int " count );
  44 .fi
  45 .SH DESCRIPTION
  46 This is not the function you are interested in.
  47 Look at
  48 .BR readdir (3)
  49 for the POSIX conforming C library interface.
  50 This page documents the bare kernel system call interface,
  51 which can change, and which is superseded by
  52 .BR getdents (2).
  53 .PP
  54 .BR readdir ()
  55 reads one
  56 .I dirent
  57 structure from the directory
  58 pointed at by
  59 .I fd
  60 into the memory area pointed to by
  61 .IR dirp .
  62 The parameter
  63 .I count
  64 is ignored; at most one dirent structure is read.
  65 .PP
  66 The
  67 .I dirent
  68 structure is declared as follows:
  69 .PP
  70 .RS
  71 .nf
  72 struct dirent
  73 {
  74     long d_ino;                 /* inode number */
  75     off_t d_off;                /* offset to this \fIdirent\fP */
  76     unsigned short d_reclen;    /* length of this \fId_name\fP */
  77     char d_name [NAME_MAX+1];   /* filename (null-terminated) */
  78 }
  79 .fi
  80 .RE
  81 .PP
  82 .I d_ino
  83 is an inode number.
  84 .I d_off
  85 is the distance from the start of the directory to this
  86 .IR dirent .
  87 .I d_reclen
  88 is the size of
  89 .IR d_name ,
  90 not counting the null terminator.
  91 .I d_name
  92 is a null-terminated filename.
  93 .SH "RETURN VALUE"
  94 On success, 1 is returned.
  95 On end of directory, 0 is returned.
  96 On error, \-1 is returned, and
  97 .I errno
  98 is set appropriately.
  99 .SH ERRORS
 100 .TP
 101 .B EBADF
 102 Invalid file descriptor
 103 .IR fd .
 104 .TP
 105 .B EFAULT
 106 Argument points outside the calling process's address space.
 107 .TP
 108 .B EINVAL
 109 Result buffer is too small.
 110 .TP
 111 .B ENOENT
 112 No such directory.
 113 .TP
 114 .B ENOTDIR
 115 File descriptor does not refer to a directory.
 116 .SH "CONFORMING TO"
 117 This system call is Linux specific.
 118 .SH "SEE ALSO"
 119 .BR getdents (2),
 120 .BR readdir (3)