Arguments

 

devnam

   OpenVMS usage:device_name
   type:         character-coded text string
   access:       read only
   mechanism:    by 32- or 64-bit descriptor-fixed-length string
                 descriptor
   Name of the device to which $ASSIGN is to assign a channel.
   The devnam argument is the 32- or 64-bit address of a character
   string descriptor pointing to the device name string.

   If the device name contains a double colon (::),  the system
   assigns a channel to the first available network device (NET:)
   and performs an access function on the network.
 

chan

   OpenVMS usage:channel
   type:         word (unsigned)
   access:       write only
   mechanism:    by 32- or 64-bit reference
   Number of the channel that is assigned. The chan argument is the
   32- or 64-bit address of a word into which $ASSIGN writes the
   channel number.
 

acmode

   OpenVMS usage:access_mode
   type:         longword (unsigned)
   access:       read only
   mechanism:    by value
   Access mode to be associated with the channel. The acmode
   argument specifies the access mode. The $PSLDEF macro defines
   the following symbols for the four access modes:

   Symbol        Access Mode   Numeric Value

   PSL$C_KERNEL  Kernel        0
   PSL$C_EXEC    Executive     1
   PSL$C_SUPER   Supervisor    2
   PSL$C_USER    User          3

   The specified access mode and the access mode of the caller are
   compared. The less privileged (but the higher numeric valued) of
   the two access modes becomes the access mode associated with the
   assigned channel. I/O operations on the channel can be performed
   only from equal and more privileged access modes. For more
   information, see the section on access modes in the VSI OpenVMS
   Programming Concepts Manual.
 

mbxnam

   OpenVMS usage:device_name
   type:         character-coded text string
   access:       read only
   mechanism:    by 32- or 64-bit descriptor-fixed-length string
                 descriptor
   Logical name of the mailbox to be associated with the device.
   The mbxnam argument is the 32- or 64-bit address of a character
   string descriptor pointing to the logical name string.

   If you specify mbxnam as 0, no mailbox is associated with the
   device. This is the default.

   You must specify the mbxnam argument when performing a
   nontransparent, task-to-task, network operation.

   Only the owner of a device can associate a mailbox with the
   device; the owner of a device is the process that has allocated
   the device, whether implicitly or explicitly. Only one mailbox
   can be associated with a device at any one time.

   For unshareable, nonspooled devices, an implicit $ALLOCATE is
   done. This requires read, write, or control access to the device.

   A mailbox cannot be associated with a device if the device has
   foreign (DEV$M_FOR) or shareable (DEV$M_SHR) characteristics.

   A mailbox is disassociated from a device when the channel that
   associated it is deassigned.

   If a mailbox is associated with a device, the device driver can
   send status information to the mailbox. For example, if the
   device is a terminal, this information might indicate dialup,
   hangup, or the reception of unsolicited input; if the device is a
   network device, it might indicate that the network is connected
   or perhaps that the line is down.

   For details on the nature and format of the information returned
   to the mailbox, see the VSI OpenVMS I/O User's Reference Manual.
 

flags

   OpenVMS usage:mask_longword
   type:         longword (unsigned)
   access:       read only
   mechanism:    by value
   An optional device-specific argument. The flags argument is a
   longword bit mask.

   For more information on the applicability of the flags argument
   for a particular device, see the VSI OpenVMS I/O User's Reference
   Manual.