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Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)getdirentries.2 8.2 (Berkeley) 5/3/95 .\" $FreeBSD$ .\" .Dd May 3, 1995 .Dt GETDIRENTRIES 2 .Os .Sh NAME .Nm getdirentries , .Nm getdents .Nd "get directory entries in a filesystem independent format" .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In sys/types.h .In dirent.h .Ft int .Fn getdirentries "int fd" "char *buf" "int nbytes" "long *basep" .Ft int .Fn getdents "int fd" "char *buf" "int nbytes" .Sh DESCRIPTION The .Fn getdirentries and .Fn getdents functions read directory entries from the directory referenced by the file descriptor .Fa fd into the buffer pointed to by .Fa buf , in a filesystem independent format. Up to .Fa nbytes of data will be transferred. The .Fa nbytes argument must be greater than or equal to the block size associated with the file, see .Xr stat 2 . Some filesystems may not support these functions with buffers smaller than this size. .Pp The data in the buffer is a series of .Em dirent structures each containing the following entries: .Bd -literal -offset indent u_int32_t d_fileno; u_int16_t d_reclen; u_int8_t d_type; u_int8_t d_namlen; char d_name[MAXNAMELEN + 1]; /* see below */ .Ed .Pp The .Fa d_fileno entry is a number which is unique for each distinct file in the filesystem. Files that are linked by hard links (see .Xr link 2 ) have the same .Fa d_fileno . The .Fa d_reclen entry is the length, in bytes, of the directory record. The .Fa d_type entry is the type of the file pointed to by the directory record. The file type values are defined in .Fa . The .Fa d_name entry contains a null terminated file name. The .Fa d_namlen entry specifies the length of the file name excluding the null byte. Thus the actual size of .Fa d_name may vary from 1 to .Dv MAXNAMELEN \&+ 1. .Pp Entries may be separated by extra space. The .Fa d_reclen entry may be used as an offset from the start of a .Fa dirent structure to the next structure, if any. .Pp The actual number of bytes transferred is returned. The current position pointer associated with .Fa fd is set to point to the next block of entries. The pointer may not advance by the number of bytes returned by .Fn getdirentries or .Fn getdents . A value of zero is returned when the end of the directory has been reached. .Pp The .Fn getdirentries function writes the position of the block read into the location pointed to by .Fa basep . Alternatively, the current position pointer may be set and retrieved by .Xr lseek 2 . The current position pointer should only be set to a value returned by .Xr lseek 2 , a value returned in the location pointed to by .Fa basep .Pf ( Fn getdirentries only) or zero. .Sh IMPLEMENTATION NOTES In the non-threaded library .Fn getdirentries is implemented as the .Va getdirentries syscall. .Pp In the threaded library, the .Va getdirentries syscall is assembled to .Fn _thread_sys_getdirentries and .Fn getdirentries is implemented as a function which locks .Fa fd for read and write, then calls .Fn _thread_sys_getdirentries . Before returning, .Fn getdirentries unlocks .Fa fd . .Sh RETURN VALUES If successful, the number of bytes actually transferred is returned. Otherwise, -1 is returned and the global variable .Va errno is set to indicate the error. .Sh ERRORS .Fn Getdirentries will fail if: .Bl -tag -width Er .It Bq Er EBADF .Fa fd is not a valid file descriptor open for reading. .It Bq Er EFAULT Either .Fa buf or .Fa basep point outside the allocated address space. .It Bq Er EINVAL The file referenced by .Fa fd is not a directory, or .Fa nbytes is too small for returning a directory entry or block of entries, or the current position pointer is invalid. .It Bq Er EIO An .Tn I/O error occurred while reading from or writing to the file system. .El .Sh SEE ALSO .Xr lseek 2 , .Xr open 2 .Sh HISTORY The .Fn getdirentries function first appeared in .Bx 4.4 . The .Fn getdents function first appeared in .Fx 3.0 .