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@(#)getdirentries.2 8.2 (Berkeley) 5/3/95
$FreeBSD: releng/11.0/lib/libc/sys/getdirentries.2 296565 2016-03-09 13:45:03Z trasz $
.Dd May 3, 1995 .Dt GETDIRENTRIES 2 .Os .Sh NAME .Nm getdirentries , .Nm getdents .Nd "get directory entries in a file system independent format" .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/types.h n 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 system calls read directory entries from the directory referenced by the file descriptor .Fa fd into the buffer pointed to by .Fa buf , in a file system 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 file systems may not support these system calls with buffers smaller than this size.
p The data in the buffer is a series of .Vt dirent structures each containing the following entries: d -literal -offset indent uint32_t d_fileno; uint16_t d_reclen; uint8_t d_type; uint8_t d_namlen; char d_name[MAXNAMLEN + 1]; /* see below */ .Ed
p The .Fa 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 .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 <sys/dirent.h> . 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 MAXNAMLEN + 1.
p 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.
p 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.
p The .Fn getdirentries system call 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
o Fn getdirentries only
c or zero. .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 The .Fn getdirentries system call will fail if: l -tag -width Er t Bq Er EBADF The .Fa fd argument is not a valid file descriptor open for reading. t Bq Er EFAULT Either .Fa buf or .Fa basep point outside the allocated address space. t 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. t 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 system call first appeared in x 4.4 . The .Fn getdents system call first appeared in .Fx 3.0 .