1. dollar
  2. Introduction
  3. $
  4. Authors
  5. License
  6. Version History

dollar

Introduction

A convenience macro for direct calls to foreign functions.

Note: this extension is only needed for CHICKEN versions 2.425 and higher

$

[syntax] ($ [RETURNTYPE] NAME (TYPE ARGUMENT) ...)

Invokes a C/C++ function by evaluating the arguments, performing the neccessary type-conversions for the foreign type-specifiers and calling NAME (which must be a symbol). If a return-type is given, then the result will be converted properly and returned. Callbacks into Scheme are not allowed inside the invoked foreign code. The type/argument lists may also be literal Scheme data or expressions of the form (quote LITERAL) or (location ...) - in this case the arguments are converted according to the type of the literal or are treated as a c-pointer, respectively. Booleans, characters, numbers, strings, SRFI-4 number vectors and symbols are converted, all other data is passed as being of type scheme-object.

($ printf "%d times Hello, %s!\n" 1000 "world")

(define f 99.2)

(let-location ((double n))
  (let ((f ($ double modf (double f) (location n))))
    (cons n f) ) )

If no return type is given, void is assumed. This macro expands into one of the foreign-lambda*, foreign-code or foreign-value forms.

Authors

felix winkelmann

License

Copyright (c) 2000-2006, Felix L. Winkelmann
All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following
conditions are met:
  Redistributions of source code must retain the above copyright notice, this list of conditions and the following
    disclaimer. 
  Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following
    disclaimer in the documentation and/or other materials provided with the distribution. 
  Neither the name of the author nor the names of its contributors may be used to endorse or promote
    products derived from this software without specific prior written permission. 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

Version History

1.0
initial release