readdir

READDIR(2)                 Linux Programmer's Manual                READDIR(2)

NAME
       readdir - read directory entry

SYNOPSIS
       int readdir(unsigned int fd, struct old_linux_dirent *dirp,
                   unsigned int count);

       Note: There is no glibc wrapper for this system call; see NOTES.

DESCRIPTION
       This is not the function you are interested in.  Look at readdir(3) for
       the POSIX conforming C library interface.  This page documents the bare
       kernel system call interface, which is superseded by getdents(2).

       readdir()  reads  one old_linux_dirent structure from the directory re-
       ferred to by the file descriptor fd into the buffer pointed to by dirp.
       The  argument  count is ignored; at most one old_linux_dirent structure
       is read.

       The old_linux_dirent structure is declared (privately in  Linux  kernel
       file fs/readdir.c) as follows:

           struct old_linux_dirent {
               unsigned long d_ino;     /* inode number */
               unsigned long d_offset;  /* offset to this old_linux_dirent */
               unsigned short d_namlen; /* length of this d_name */
               char  d_name[1];         /* filename (null-terminated) */
           }

       d_ino  is  an inode number.  d_offset is the distance from the start of
       the directory to  this  old_linux_dirent.   d_reclen  is  the  size  of
       d_name,  not  counting  the  terminating null byte ('\0').  d_name is a
       null-terminated filename.

RETURN VALUE
       On success, 1 is returned.  On end of directory, 0 is returned.  On er-
       ror, -1 is returned, and errno is set appropriately.

ERRORS
       EBADF  Invalid file descriptor fd.

       EFAULT Argument points outside the calling process's address space.

       EINVAL Result buffer is too small.

       ENOENT No such directory.

       ENOTDIR
              File descriptor does not refer to a directory.

CONFORMING TO
       This system call is Linux-specific.

NOTES
       Glibc  does  not  provide a wrapper for this system call; call it using
       syscall(2).  You will need to  define  the  old_linux_dirent  structure
       yourself.  However, probably you should use readdir(3) instead.

       This system call does not exist on x86-64.

SEE ALSO
       getdents(2), readdir(3)

COLOPHON
       This  page  is  part of release 5.05 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       https://www.kernel.org/doc/man-pages/.

Linux                             2019-03-06                        READDIR(2)