uio(9s) uio(9s)
NAME
uio - General: Describes I/O, either single vector or multiple vectors
SYNOPSIS
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Member Name Data Type
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uio_iov struct iovec *
uio_iovcnt int
uio_offset off_t
uio_segflg enum uio_seg
uio_resid int
uio_rw enum uio_rw
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MEMBERS
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 num-
ber 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
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
SEE ALSO
Routines: uiomove(9r)
uio(9s)