Arguments: name-and-options &key type convention
This macro creates the specification which allows lisp to correctly reference non-lisp variable data. Like other defining forms, its macroexpansion clearly shows what will occur and at what eval-when times. The execution of the expanded form always returns the lisp name being defined. The definition that is installed is a symbol-macro that accesses the non-lisp value correctly.
name-and-options can either be a symbol or a list of a
symbol and an external-name specification. The symbol represents the
lisp-name for which the foreign-variable definition will be
installed. The external name specification can be either a string
specifying a literal external name, or it can be a symbol, which
represents the name of a conversion function. That conversion function
must take one required argument and at least the language keyword
argument, and must be defined at the time the macro expansion is
executed. At that time this conversion function will be called and
will receive the lisp-name specified, as well as the arguments
:language lang where lang is the value
of the convention keyword.
type is the access type of the variable, and can be any of the valid access
types for memref and memref-int. The default access type is :unsigned-long.
convention is used by the macro to properly translate the lisp name into a
foreign name, and is given to the conversion function as its language keyword
argument. The possible values are :c and :fortran.
See ftype.htm for information on foreign types in Allegro CL and foreign-functions.htm for general information on foreign functions in Allegro CL.
The documentation is described in introduction.htm and the index is in index.htm.
Copyright (c) 1998-2000, Franz Inc. Berkeley, CA., USA. All rights reserved.
Created 2000.10.5.