.\" Copyright (C) 1995 Andries Brouwer (aeb@cwi.nl) .\" .\" SPDX-License-Identifier: Linux-man-pages-copyleft .\" .\" Written 11 June 1995 by Andries Brouwer .\" Modified 22 July 1995 by Michael Chastain : .\" In 1.3.X, returns only one entry each time; return value is different. .\" Modified 2004-12-01, mtk, fixed headers listed in SYNOPSIS .\" .TH readdir 2 2024-06-15 "Linux man-pages 6.9.1" .SH NAME readdir \- read directory entry .SH LIBRARY Standard C library .RI ( libc ", " \-lc ) .SH SYNOPSIS .nf .BR "#include " " /* Definition of " SYS_* " constants */" .B #include .P .BI "int syscall(SYS_readdir, unsigned int " fd , .BI " struct old_linux_dirent *" dirp ", unsigned int " count ); .fi .P .IR Note : There is no definition of .BR "struct old_linux_dirent" ; see NOTES. .SH DESCRIPTION This is not the function you are interested in. Look at .BR readdir (3) for the POSIX conforming C library interface. This page documents the bare kernel system call interface, which is superseded by .BR getdents (2). .P .BR readdir () reads one .I old_linux_dirent structure from the directory referred to by the file descriptor .I fd into the buffer pointed to by .IR dirp . The argument .I count is ignored; at most one .I old_linux_dirent structure is read. .P The .I old_linux_dirent structure is declared (privately in Linux kernel file .BR fs/readdir.c ) as follows: .P .in +4n .EX struct old_linux_dirent { unsigned long d_ino; /* inode number */ unsigned long d_offset; /* offset to this \fIold_linux_dirent\fP */ unsigned short d_namlen; /* length of this \fId_name\fP */ char d_name[1]; /* filename (null\-terminated) */ } .EE .in .P .I d_ino is an inode number. .I d_offset is the distance from the start of the directory to this .IR old_linux_dirent . .I d_reclen is the size of .IR d_name , not counting the terminating null byte (\[aq]\[rs]0\[aq]). .I d_name is a null-terminated filename. .SH RETURN VALUE On success, 1 is returned. On end of directory, 0 is returned. On error, \-1 is returned, and .I errno is set to indicate the error. .SH ERRORS .TP .B EBADF Invalid file descriptor .IR fd . .TP .B EFAULT Argument points outside the calling process's address space. .TP .B EINVAL Result buffer is too small. .TP .B ENOENT No such directory. .TP .B ENOTDIR File descriptor does not refer to a directory. .SH VERSIONS You will need to define the .I old_linux_dirent structure yourself. However, probably you should use .BR readdir (3) instead. .P This system call does not exist on x86-64. .SH STANDARDS Linux. .SH SEE ALSO .BR getdents (2), .BR readdir (3)