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getdirentries(2)            BSD System Calls Manual           getdirentries(2)


NAME

     getdirentries -- get directory entries in a filesystem independent format


SYNOPSIS

     #include <dirent.h>
     #include <sys/types.h>
     #include <sys/dirent.h>

     int
     getdirentries(int fd, char *buf, int nbytes, long *basep);


DESCRIPTION

     Getdirentries() reads directory entries from the directory referenced by
     the file descriptor fd into the buffer pointed to by buf, in a filesystem
     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 filesystems may not support getdirentries() with
     buffers smaller than this size.

     The data in the buffer is a series of dirent structures (see dir(5))

     The d_fileno entry is a number which is unique for each distinct file in
     the filesystem.  Files that are linked by hard links (see link(2)) have
     the same d_fileno.  Users of getdirentries() should skip entries with
     d_fileno = 0, as such entries represent files which have been deleted but
     not yet removed from the directory entry.  The d_reclen entry is the
     length, in bytes, of the directory record.  The d_name entry contains a
     null terminated file name.  The d_namlen entry specifies the length of
     the file name excluding the null byte.  Thus the actual size of d_name
     may vary from 1 to MAXNAMELEN + 1.  d_type is a integer representing the
     type of the directory entry.  The following types are defined in
     <sys/dirent.h>:

           #define DT_UNKNOWN       0
           #define DT_FIFO          1
           #define DT_CHR           2
           #define DT_DIR           4
           #define DT_BLK           6
           #define DT_REG           8
           #define DT_LNK          10
           #define DT_SOCK         12
           #define DT_WHT          14

     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
     getdirentries().  A value of zero is returned when the end of the direc-
     tory has been reached.

     Getdirentries() writes the position of the block read into the location
     pointed to by basep.  Alternatively, 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), a value returned in the location
     pointed to by basep, or zero.


NOTES

     getdirentries() should rarely be used directly; instead, opendir(3) and
     readdir(3) should be used.

     As of Mac OS X 10.6, getdirentries() is deprecated, and it is recommended
     that applications use readdir(3) rather than using getdirentries()
     directly.  Due to limitations with the system call, getdirentries() will
     not work with 64-bit inodes; in order to use getdirentries(),
     _DARWIN_NO_64_BIT_INODE must be defined.  See stat(2) for more informa-
     tion on _DARWIN_NO_64_BIT_INODE and its other effects.


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

     Getdirentries() will fail if:

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

     [EFAULT]           Either buf or basep point outside the allocated
                        address space.

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


SEE ALSO

     lseek(2), open(2), stat(2), opendir(3), readdir(3), dir(5)


HISTORY

     The getdirentries() function first appeared in 4.4BSD.

BSD                              June 9, 1993                              BSD

Mac OS X 10.9.1 - Generated Sun Jan 5 20:59:42 CST 2014
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