GETDIRENTRIES(2) BSD System Calls Manual GETDIRENTRIES(2)
getdirentries, getdents -- get directory entries in a file system independent format
Standard C Library (libc, -lc)
getdirentries(int fd, char *buf, int nbytes, long *basep);
getdents(int fd, char *buf, int nbytes);
The getdirentries() and getdents() system calls read 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. The nbytes argument must be
greater than or equal to the block size associated with the file, see stat(2) . Some file
systems may not support these system calls with buffers smaller than this size.
The data in the buffer is a series of dirent structures each containing the following
char d_name[MAXNAMELEN + 1]; /* see below */
The d_fileno entry is a number which is unique for each distinct file in the file system.
Files that are linked by hard links (see link(2) ) have the same d_fileno. The d_reclen
entry is the length, in bytes, of the directory record. The d_type entry is the type of the
file pointed to by the directory record. The file type values are defined in
<sys/dirent.h>. 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.
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() or getdents(). A value of zero is returned when
the end of the directory has been reached.
The getdirentries() system call 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 (getdirentries() only) or
If successful, the number of bytes actually transferred is returned. Otherwise, -1 is
returned and the global variable errno is set to indicate the error.
The getdirentries() system call will fail if:
[EBADF] The fd argument is not a valid file descriptor open for reading.
[EFAULT] Either buf or basep point outside the allocated address space.
[EINVAL] The file referenced by fd is not a directory, or nbytes is too small for
returning a directory entry or block of entries, or the current position
pointer is invalid.
[EIO] An I/O error occurred while reading from or writing to the file system.
lseek(2) , open(2)
The getdirentries() system call first appeared in 4.4BSD. The getdents() system call first
appeared in FreeBSD 3.0.
BSD May 3, 1995 BSD