vdmdummy(7)                    DG/UX 5.4R3.00                    vdmdummy(7)


NAME
       vdmdummy - Dummy Subdriver of the Virtual Disk Manager

SYNOPSIS
       #include <types.h>
       #include <ioctl.h>

       ioctl(int fildes, int command, int argument);

DESCRIPTION
       The Dummy Subdriver is a pseudo-device driver that works under the
       Virtual Disk Management (VDM) framework (see vdm(7)).  The purpose of
       the Dummy Subdriver is to provide place holder instances for various
       VDM commands involving the movement of an instances functionality.
       The key feature of a dummy instance is that it has no attributes.

STRUCTURES
       The structures defined in this section are pointed to by fields
       described in VDM commands (see vdm(7)).  The VDM command and the
       field in the argument structure will be described.  For many VDM
       commands, a subdriver ID is required as an input value.  The
       subdriver ID for the Dummy Subdriver is defined by
       DGVDMDUMMYSUBDRIVERID.

   DGVDMCREATEINSTANCE
       Because dummy instances have no attributes, no create packet is used
       to accompany the VDM create command.

   DGVDMLINKCHILDINSTANCE
       Because dummy instances have no children, no child can be added.

   DGVDMGETCHILDINSTANCE
       Because dummy instances have no children, no child can be obtained.

   DGVDMGETATTRIBUTES
       This command is not supported by the Dummy Subdriver.

   DGVDMUPDATEATTRIBUTES
       This command is not supported by the Dummy Subdriver.

   DGVDMEXTRACTINSTANCE
       Because dummy instances have no children, no child functionality can
       be extracted from the dummy instance and replaced with its child.

   DGVDMUNLINKCHILDINSTANCE
       Because dummy instances have no children, no child can be unlinked.

IOCTLS
       There are no ioctls supported by the Dummy Subdriver.

EXAMPLE
       #include <errno.h>
       #include <fcntl.h>
       #include <stdio.h>



Licensed material--property of copyright holder(s)                         1

vdmdummy(7)                    DG/UX 5.4R3.00                    vdmdummy(7)


       #include <string.h>
       #include <sys/dgsysctl.h>
       #include <sys/ioctl.h>
       #include <unistd.h>

       /*
        *  This example makes use of the vdmioctl() function described in the
        *  vdm(7) man page.  The vdmioctl() function issues ioctl(2) commands
        *  to the /dev/vdm device node.
        */

       int main (void)
       {
       int                                  status;
       struct dgvdmcreateinstancepacket createinstancepkt;
       struct dgvdmdummycreatepacket    createdummypkt;

       /*
        *  Create a dummy instance.
        */

       createinstancepkt.subdriverid = DGVDMDUMMYSUBDRIVERID;
       createinstancepkt.subdriverattributespacketptr = NULL;
       strcpy(createinstancepkt.instancename, "a");

       status = vdmioctl(DGVDMCREATEINSTANCE, &createinstancepkt);
       if (status == -1)
           {
           perror("create a");
           exit(1);
           }

       exit(0);
       }


FILES
       Files in or under /dev

SEE ALSO
       vdm(7), ioctl(2).
















Licensed material--property of copyright holder(s)                         2