readdir(2)

1readdir(2)                    System Calls Manual                   readdir(2)
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NAME

6       readdir - read directory entry
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

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

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23       kernel system call interface, which is superseded by getdents(2).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

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

50       EBADF  Invalid file descriptor fd.
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52       EFAULT Argument points outside the calling process's address space.
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54       EINVAL Result buffer is too small.
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56       ENOENT No such directory.
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58       ENOTDIR
59              File descriptor does not refer to a directory.
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VERSIONS

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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STANDARDS

68       Linux.
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