module_info(D4)

NAME
     module_info - STREAMS driver and module information structure

SYNOPSIS
     #include <sys/types.h>
     #include <sys/conf.h>
     #include <sys/stream.h>
     #include <sys/ddi.h>

DESCRIPTION
     When a module or driver is declared, several identification and limit
     values can be set.  These values are stored in the module_info structure.
     These values are used to initialize the module's or driver's queues when
     they are created.

USAGE
     After the initial declaration, the module_info structure is intended to
     be read-only.  However, the flow control limits (mi_hiwat and mi_lowat)
     and the packet size limits (mi_minpsz and mi_maxpsz) are copied to the
     queue(D4) structure, where they may be modified.

     There may be one module_info structure per read and write queue, or the
     driver or module may use the same module_info structure for both the read
     and write queues.

   Structure Definitions
     The module_info structure contains the following members:

     ushort_t  mi_idnum;    /* module ID number */
     char      *mi_idname;  /* module name */
     long      mi_minpsz;   /* minimum packet size */
     long      mi_maxpsz;   /* maximum packet size */
     ulong_t   mi_hiwat;    /* high water mark */
     ulong_t   mi_lowat;    /* low water mark */
     The mi_idnum field is a unique identifier for the driver or module that
     distinguishes the driver or module from the other drivers and modules in
     the system.

     The mi_idname field points to the driver or module name.  The constant
     FMNAMESZ limits the length of the name, not including the terminating
     NULL.  It is currently set to eight characters.

     The mi_minpsz field is the default minimum packet size for the driver or
     module queues.  This is an advisory limit specifying the smallest message
     that can be accepted by the driver or module.

     The mi_maxpsz field is the default maximum packet size for the driver or
     module queues.  This is an advisory limit specifying the largest message
     that can be accepted by the driver or module.
     The mi_hiwat field is the default high water mark for the driver or
     module queues.  This specifies the number of bytes of data contained in
     messages on the queue such that the queue is considered full and hence
     flow-controlled.

     The mi_lowat field is the default low water mark for the driver or module
     queues.  This specifies the number of bytes of data contained in messages
     on the queue such that the queue is no longer flow-controlled.

REFERENCES
     queue(D4)