DIRREAD(2)DIRREAD(2)NAME
dirread, dirreadall - read directory
SYNOPSIS
#include <u.h>
#include <libc.h>
long dirread(int fd, Dir **buf)
long dirreadall(int fd, Dir **buf)
#define STATMAX 65535U
#define DIRMAX (sizeof(Dir)+STATMAX)
DESCRIPTION
The data returned by a read(2) on a directory is a set of complete
directory entries in a machine-independent format, exactly equivalent
to the result of a stat(2) on each file or subdirectory in the direc‐
tory. Dirread decodes the directory entries into a machine-dependent
form. It reads from fd and unpacks the data into an array of Dir
structures whose address is returned in *buf (see stat(2) for the lay‐
out of a Dir). The array is allocated with malloc(2) each time dirread
is called.
Dirreadall is like dirread, but reads in the entire directory; by con‐
trast, dirread steps through a directory one read(2) at a time.
Directory entries have variable length. A successful read of a direc‐
tory always returns an integral number of complete directory entries;
dirread always returns complete Dir structures. See read(5) for more
information.
The constant STATMAX is the maximum size that a directory entry can
occupy. The constant DIRMAX is an upper limit on the size necessary to
hold a Dir structure and all the associated data.
Dirread and dirreadall return the number of Dir structures filled in
buf. The file offset is advanced by the number of bytes actually read.
SOURCE
/sys/src/libc/9sys/dirread.c
SEE ALSOintro(2), open(2), read(2)DIAGNOSTICS
Dirread and Dirreadall return zero for end of file and a negative value
for error. In either case, *buf is set to nil so the pointer can
always be freed with impunity.
These functions set errstr.
DIRREAD(2)
