readdir(3B) manual page
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readdir - read a directory entry
/usr/ucb/cc [ flag ... ] file
...
#include <sys/types.h>
#include <sys/dir.h>
struct direct *readdir(dirp);
DIR *dirp;
readdir() returns a pointer to a structure representing
the directory entry at the current position in the directory stream to
which dirp refers, and positions the directory stream at the next entry,
except on read-only filesystems. It returns a NULL
pointer upon reaching
the end of the directory stream, or upon detecting an invalid location
in the directory. readdir() shall not return directory entries containing
empty names. It is unspecified whether entries are returned for dot or
dot-dot. The pointer returned by readdir() points to data that may be overwritten
by another call to readdir() on the same directory stream. This data shall
not be overwritten by another call to readdir() on a different directory
stream. readdir() may buffer several directory entries per actual read
operation. readdir() marks for update the st_atime field of the directory
each time the directory is actually read.
readdir() returns
NULL
on failure and sets errno to indicate the error.
readdir()
will fail if one or more of the following are true:
- EAGAIN
- Mandatory file/record
locking was set, O_NDELAY
or O_NONBLOCK
was set, and there was a blocking
record lock.
- EAGAIN
- Total amount of system memory available when reading
using raw I/O is temporarily insufficient.
- EAGAIN
- No data is waiting to
be read on a file associated with a tty device and O_NONBLOCK
was set.
- EAGAIN
- No message is waiting to be read on a stream and O_NDELAY
or
O_NONBLOCK
was set.
- EBADF
- The file descriptor determined by the DIR
stream is no longer valid. This results if the DIR
stream has been closed.
- EBADMSG
- Message waiting to be read on a stream is not a data message.
- EDEADLK
- The read() was going to go to sleep and cause a deadlock to occur.
- EFAULT
- buf points to an illegal address.
- EINTR
- A signal was caught during the
read() or readv() function.
- EINVAL
- Attempted to read from a stream linked
to a multiplexor.
- EIO
- A physical I/O error has occurred, or the process
is in a background process group and is attempting to read from its controlling
terminal, and either the process is ignoring or blocking the SIGTTIN
signal
or the process group of the process is orphaned.
- ENOENT
- The current file
pointer for the directory is not located at a valid entry.
- ENOLCK
- The system
record lock table was full, so the read() or readv() could not go to sleep
until the blocking record lock was removed.
- ENOLINK
- fildes is on a remote
machine and the link to that machine is no longer active.
- ENXIO
- The device
associated with fildes is a block special or character special file and
the value of the file pointer is out of range.
getdents(2)
, scandir(3B)
,
directory(3C)
Use of these interfaces should be restricted to only
applications written on BSD
platforms. Use of these interfaces with any
of the system libraries or in multi-thread applications is unsupported.
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