1READDIR(2)                 Linux Programmer's Manual                READDIR(2)
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NAME

6       readdir - read directory entry
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SYNOPSIS

9       #include <sys/syscall.h>      /* Definition of SYS_* constants */
10       #include <unistd.h>
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12       int syscall(SYS_readdir, unsigned int fd,
13                   struct old_linux_dirent *dirp, unsigned int count);
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15       Note: There is no definition of struct old_linux_dirent; see NOTES.
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DESCRIPTION

18       This is not the function you are interested in.  Look at readdir(3) for
19       the POSIX conforming C library interface.  This page documents the bare
20       kernel system call interface, which is superseded by getdents(2).
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22       readdir()  reads  one old_linux_dirent structure from the directory re‐
23       ferred to by the file descriptor fd into the buffer pointed to by dirp.
24       The  argument  count is ignored; at most one old_linux_dirent structure
25       is read.
26
27       The old_linux_dirent structure is declared (privately in  Linux  kernel
28       file fs/readdir.c) as follows:
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30           struct old_linux_dirent {
31               unsigned long d_ino;     /* inode number */
32               unsigned long d_offset;  /* offset to this old_linux_dirent */
33               unsigned short d_namlen; /* length of this d_name */
34               char  d_name[1];         /* filename (null-terminated) */
35           }
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37       d_ino  is  an inode number.  d_offset is the distance from the start of
38       the directory to  this  old_linux_dirent.   d_reclen  is  the  size  of
39       d_name,  not  counting  the  terminating null byte ('\0').  d_name is a
40       null-terminated filename.
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RETURN VALUE

43       On success, 1 is returned.  On end of directory, 0 is returned.  On er‐
44       ror, -1 is returned, and errno is set to indicate the error.
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ERRORS

47       EBADF  Invalid file descriptor fd.
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49       EFAULT Argument points outside the calling process's address space.
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51       EINVAL Result buffer is too small.
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53       ENOENT No such directory.
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55       ENOTDIR
56              File descriptor does not refer to a directory.
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CONFORMING TO

59       This system call is Linux-specific.
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NOTES

62       You  will need to define the old_linux_dirent structure yourself.  How‐
63       ever, probably you should use readdir(3) instead.
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65       This system call does not exist on x86-64.
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SEE ALSO

68       getdents(2), readdir(3)
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COLOPHON

71       This page is part of release 5.12 of the Linux  man-pages  project.   A
72       description  of  the project, information about reporting bugs, and the
73       latest    version    of    this    page,    can     be     found     at
74       https://www.kernel.org/doc/man-pages/.
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78Linux                             2021-03-22                        READDIR(2)
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