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if_alloc(9r)
NAME
  if_alloc - Network: Allocates an ifnet structure large enough to hold an
  ether_driver structure

SYNOPSIS
  struct ether_driver *if_alloc(
	  char *name,
	  int unit,
	  u_int size );

ARGUMENTS
  name
      Specifies the address of a buffer containing the device name. Usually
      this is a two- or three-character name representing the network device
      (such as tu).

  unit
      Specifies the unit number for the device. This number is obtained from
      the ctlr_num member of the device's controller data structure.

  size
      Specifies the size of the structure that should be allocated. Specify a
      size at least as large as the size of the ifnet data structure defined
      in /usr/include/net/if.h.

DESCRIPTION
  The if_alloc() routine allocates a data structure of the requested size. It
  assumes that the first part of this data structure is an ifnet data
  structure. The if_alloc() routine initializes the if_name and if_unit
  members of the ifnet structure to contain the name and unit values passed
  in, respectively.

NOTES
  A network device driver calls if_alloc() to allocate an ether_driver data
  structure for the network device.

EXAMPLE
  The following example shows how to use if_alloc():

	       struct nd_softc {
		       struct ether_driver *is_ed;
		       ...
	       } sc;

	       static int nd_probe(struct controller *ctlr)
	       {
		       ...
		       sc.is_ed = if_alloc("nd", ctlr->ctlr_num,
					   sizeof(struct ether_driver));
		       if (sc.is_ed)
			       return (0);
		       ....

	       }

RETURN VALUES
  NULL if any of the arguments passed in are invalid, such as 0 for size or
  NULL for name.

  Upon success, the address of a memory buffer is returned to the caller of
  the size indicated, with the if_name and if_unit members of the ifnet
  structure initialized.

SEE ALSO
  Routines: if_attach(9r), if_detach(9r), if_dealloc(9r)

Index for Section 9

Alphabetical listing for I

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