Arguments

 

efn

   OpenVMS usage:ef_number
   type:         longword (unsigned)
   access:       read only
   mechanism:    by value
   Event flag that $QIO is to set when the I/O operation completes.
   The efn argument is a longword value containing the number of the
   event flag; however, $QIO uses only the low-order byte.
 

chan

   OpenVMS usage:channel
   type:         word (unsigned)
   access:       read only
   mechanism:    by value
   I/O channel assigned to the device to which the request is
   directed. The chan argument is a word value containing the number
   of the I/O channel; however, $QIO uses only the low-order word.

   Specifying an invalid value for the chan argument will result in
   either SS$_IVCHAN or SS$_IVIDENT being returned.
 

func

   OpenVMS usage:function_code
   type:         longword (unsigned)
   access:       read only
   mechanism:    by value
   Device-specific function codes and function modifiers specifying
   the operation to be performed. The func argument is a longword
   containing the function code.
 

iosb

   OpenVMS usage:io_status_block
   type:         quadword (unsigned)
   access:       write only
   mechanism:    by 32- or 64-bit reference (Alpha and Integrity
                 servers)
   I/O status block to receive the final completion status of the
   I/O operation. The iosb argument is the address of the quadword
   I/O status block.
 

astadr

   OpenVMS usage:ast_procedure
   type:         procedure value
   access:       call without stack unwinding
   mechanism:    by 32- or 64-bit reference (Alpha and Integrity
                 servers)
   AST service routine to be executed when the I/O completes. The
   astadr argument is the address of the AST routine.

   The AST routine executes at the access mode of the caller of
   $QIO.
 

astprm

   OpenVMS usage:user_arg
   type:         quadword unsigned (Alpha and Integrity servers)
   access:       read only
   mechanism:    by 64-bit value (Alpha and Integrity servers)
   AST parameter to be passed to the AST service routine. On Alpha
   and Integrity server systems, the astprm argument is a quadword
   value containing the AST parameter.
 

p1 to p6

   OpenVMS usage:varying_arg
   type:         quadword (unsigned) (Alpha and Integrity servers)
   access:       read only
   mechanism:    by 32- or 64-bit reference or by 64-bit value,
                 depending on the I/O function (Alpha and Integrity
                 servers)
   Optional device-specific and function-specific I/O request
   parameters.