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Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)getdirentries.2 8.2 (Berkeley) 5/3/95 33.\" $FreeBSD: src/lib/libc/sys/getdirentries.2,v 1.12.2.6 2001/12/14 18:34:00 ru Exp $ 34.\" $DragonFly: src/lib/libc/sys/getdirentries.2,v 1.2 2003/06/17 04:26:47 dillon Exp $ 35.\" 36.Dd May 3, 1995 37.Dt GETDIRENTRIES 2 38.Os 39.Sh NAME 40.Nm getdirentries , 41.Nm getdents 42.Nd "get directory entries in a filesystem independent format" 43.Sh LIBRARY 44.Lb libc 45.Sh SYNOPSIS 46.In sys/types.h 47.In dirent.h 48.Ft int 49.Fn getdirentries "int fd" "char *buf" "int nbytes" "long *basep" 50.Ft int 51.Fn getdents "int fd" "char *buf" "int nbytes" 52.Sh DESCRIPTION 53The 54.Fn getdirentries 55and 56.Fn getdents 57functions read directory entries from the directory 58referenced by the file descriptor 59.Fa fd 60into the buffer pointed to by 61.Fa buf , 62in a filesystem independent format. 63Up to 64.Fa nbytes 65of data will be transferred. 66The 67.Fa nbytes 68argument must be greater than or equal to the 69block size associated with the file, 70see 71.Xr stat 2 . 72Some filesystems may not support these functions 73with buffers smaller than this size. 74.Pp 75The data in the buffer is a series of 76.Em dirent 77structures each containing the following entries: 78.Bd -literal -offset indent 79u_int32_t d_fileno; 80u_int16_t d_reclen; 81u_int8_t d_type; 82u_int8_t d_namlen; 83char d_name[MAXNAMELEN + 1]; /* see below */ 84.Ed 85.Pp 86The 87.Fa d_fileno 88entry is a number which is unique for each 89distinct file in the filesystem. 90Files that are linked by hard links (see 91.Xr link 2 ) 92have the same 93.Fa d_fileno . 94The 95.Fa d_reclen 96entry is the length, in bytes, of the directory record. 97The 98.Fa d_type 99entry is the type of the file pointed to by the directory record. 100The file type values are defined in 101.Fa <sys/dirent.h> . 102The 103.Fa d_name 104entry contains a null terminated file name. 105The 106.Fa d_namlen 107entry specifies the length of the file name excluding the null byte. 108Thus the actual size of 109.Fa d_name 110may vary from 1 to 111.Dv MAXNAMELEN 112\&+ 1. 113.Pp 114Entries may be separated by extra space. 115The 116.Fa d_reclen 117entry may be used as an offset from the start of a 118.Fa dirent 119structure to the next structure, if any. 120.Pp 121The actual number of bytes transferred is returned. 122The current position pointer associated with 123.Fa fd 124is set to point to the next block of entries. 125The pointer may not advance by the number of bytes returned by 126.Fn getdirentries 127or 128.Fn getdents . 129A value of zero is returned when 130the end of the directory has been reached. 131.Pp 132The 133.Fn getdirentries 134function writes the position of the block read into the location pointed to by 135.Fa basep . 136Alternatively, the current position pointer may be set and retrieved by 137.Xr lseek 2 . 138The current position pointer should only be set to a value returned by 139.Xr lseek 2 , 140a value returned in the location pointed to by 141.Fa basep 142.Pf ( Fn getdirentries 143only) 144or zero. 145.Sh RETURN VALUES 146If successful, the number of bytes actually transferred is returned. 147Otherwise, -1 is returned and the global variable 148.Va errno 149is set to indicate the error. 150.Sh ERRORS 151.Fn Getdirentries 152will fail if: 153.Bl -tag -width Er 154.It Bq Er EBADF 155.Fa fd 156is not a valid file descriptor open for reading. 157.It Bq Er EFAULT 158Either 159.Fa buf 160or 161.Fa basep 162point outside the allocated address space. 163.It Bq Er EINVAL 164The file referenced by 165.Fa fd 166is not a directory, or 167.Fa nbytes 168is too small for returning a directory entry or block of entries, 169or the current position pointer is invalid. 170.It Bq Er EIO 171An 172.Tn I/O 173error occurred while reading from or writing to the file system. 174.El 175.Sh SEE ALSO 176.Xr lseek 2 , 177.Xr open 2 178.Sh HISTORY 179The 180.Fn getdirentries 181function first appeared in 182.Bx 4.4 . 183The 184.Fn getdents 185function first appeared in 186.Fx 3.0 . 187