readdir (2) Linux Manual Page

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 This page documents the bare kernel system call interface, which is superseded by getdents(2).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 referred 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 (‘