getdents(2) - NetBSD Manual Pages

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GETDENTS(2)               NetBSD System Calls Manual               GETDENTS(2)


NAME

     getdents -- get directory entries in a file system independent format


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <dirent.h>

     int
     getdents(int fd, char *buf, size_t nbytes);


DESCRIPTION

     getdents() reads directory entries from the directory referenced by the
     file descriptor fd into the buffer pointed to by buf, in a file system
     independent format.  Up to nbytes of data will be transferred.  nbytes
     must be greater than or equal to the block size associated with the file,
     see stat(2).  Some file systems may not support getdents() with buffers
     smaller than this size.

     The data in the buffer is a series of dirent structures:

           struct dirent {
                   ino_t    d_fileno;              /* file number of entry */
                   uint16_t d_reclen;              /* length of this record */
                   uint16_t d_namlen;              /* length of d_name */
                   uint8_t  d_type;                /* file type, see below */
                   char     d_name[MAXNAMLEN + 1];
           };

     The structure is described in dirent(3).

     Entries may be separated by extra space.  The d_reclen entry may be used
     as an offset from the start of a dirent structure to the next structure,
     if any.

     The actual number of bytes transferred is returned.  The current position
     pointer associated with fd is set to point to the next block of entries.
     The pointer may not advance by the number of bytes returned by
     getdents().  A value of zero is returned when the end of the directory
     has been reached.

     The current position pointer may be set and retrieved by lseek(2).  The
     current position pointer should only be set to a value returned by
     lseek(2), or zero.


RETURN VALUES

     If successful, the number of bytes actually transferred is returned.
     Otherwise, -1 is returned and the global variable errno is set to indi-
     cate the error.


ERRORS

     getdents() will fail if:

     [EBADF]   fd is not a valid file descriptor open for reading.

     [EFAULT]  buf points outside the allocated address space.

     [EINVAL]  A directory was being read on NFS, but it was modified on the
               server while it was being read.

     [EIO]     An I/O error occurred while reading from or writing to the file
               system.


SEE ALSO

     lseek(2), open(2), dirent(3)


HISTORY

     The getdents() function first appeared in NetBSD 1.3.

NetBSD 8.0                       June 4, 2010                       NetBSD 8.0