NAME    [Toc]    [Back]

       uio - General: Describes I/O, either single vector or multiple
 vectors

SYNOPSIS    [Toc]    [Back]

       -----------------------------
       Member Name   Data Type
       -----------------------------
       uio_iov       struct iovec *
       uio_iovcnt    int
       uio_offset    off_t
       uio_segflg    enum uio_seg
       uio_resid     int
       uio_rw        enum uio_rw
       -----------------------------

MEMBERS    [Toc]    [Back]

       Specifies a pointer to  the  first  iovec  structure.  The
       iovec  structure  has  two members: one that specifies the
       address of the segment and another that specifies the size
       of  the  segment.  The  system  allocates contiguous iovec
       structures for a given transfer.  Specifies the number  of
       iovec  structures for this transfer.  Specifies the offset
       within the file.  Specifies the segment type. This  member
       can  be  set to one of the following values: UIO_USERSPACE
       (the segment is from the user  data  space),  UIO_SYSSPACE
       (the  segment is from the system space), or UIO_USERISPACE
       (the segment is from the user  I  space).   Specifies  the
       number of bytes that still need to be transferred.  Specifies
 whether the transfer is a read or a write. This  member
 is set by read and write system calls according to the
       corresponding field in the file  descriptor.  This  member
       can  be set to one of the following values: UIO_READ (read
       transfer), UIO_WRITE (write transfer), or UIO_AIORW (Alpha
       I/O read/write transfer).

DESCRIPTION    [Toc]    [Back]

       The uio data structure describes, either singler-vector or
       multiple-vector I/O.  Typically,  kernel  modules  do  not
       manipulate  the  members  of this data structure. However,
       the data structure is presented here for  the  purpose  of
       understanding  the  uiomove routine, which operates on the
       members of the uio structure.

FILES    [Toc]    [Back]

SEE ALSO
       Routines: uiomove(9r)



                                                          uio(9s)