iovec(D4) iovec(D4)
NAME
iovec - data storage structure for I/O using uio
SYNOPSIS
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/ddi.h>
DESCRIPTION
The iovec structure describes a data storage area for transfer
in a uio(D4) structure. Conceptually, it may be thought of as
a base address and length specification.
USAGE
A separate interface does not currently exist for allocating
iovec(D4) structures when the driver needs to create them
itself. Therefore, the driver may either use kmem_zalloc(D3)
to allocate them, or allocate them statically.
Structure Definitions
The iovec structure contains the following members:
caddr_t iov_base; /* base address of the data storage area */
int iov_len; /* size of the data storage area in bytes */
The driver may only set iovec structure members to initialize
them for a data transfer for which the driver created the
iovec structure. The driver must not otherwise change iovec
structure members. However, drivers may read them. The iovec
structure members available to the driver are:
iov_base contains the address for a range of memory to or from
which data are transferred.
iov_len contains the number of bytes of data to be transferred
to or from the range of memory starting at iov_base.
REFERENCES
physiock(D3), uiomove(D3), ureadc(D3), uwritec(D3), uio(D4)
NOTICES
Portability
All processors
Copyright 1994 Novell, Inc. Page 1