iovec(D4)

NAME
     iovec - data storage structure for I/O using uio(D4)

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
     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)