chickadee » dollar

dollar

Documentation

A convenience macro for direct calls to foreign functions.

$

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

Invokes a C/C++ function by evaluating the arguments, performing the neccessary type-conversions for the foreign type-specifiers TYPE ... and calling NAME (which must be a symbol).

If RETURNTYPE is given, then the result will be converted properly and returned, otherwise void is assumed.

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.

Callbacks into Scheme are not allowed inside the invoked foreign code.

This macro expands into one of the foreign-lambda*, foreign-code or foreign-value forms.

Usage

(require-extension dollar)

Examples

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

(define f 99.2) 
(let-location ((n double))
  (let ((f ($ double modf (double f) (location n))))
    (cons n f) ) )

Authors

/users/felix winkelmann and kon lovett

Version history

2.0.4
removed some unused code and dependency on setup-helper, allows import-only semantics, minor documentation fixes, added test-case
2.0.3
Fixed identifier incompatible with symbol quoting. Felix Winkelmann
2.0.2
Fix. Kon Lovett
2.0.1
Minor documentation fixes.
2.0.0
Chicken 4 release.

License

Copyright (c) 2000-2010, 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
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