daemon: Allow building for armhf-linux on aarch64-linux.

[jackhill/guix/guix.git] / guix / gcrypt.scm

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (guix gcrypt)
  #:use-module (guix config)
  #:use-module (system foreign)
  #:export (gcrypt-version
            libgcrypt-func))

;;; Commentary:
;;;
;;; Common code for the GNU Libgcrypt bindings.  Loading this module
;;; initializes Libgcrypt as a side effect.
;;;
;;; Code:

(define libgcrypt-func
  (let ((lib (dynamic-link %libgcrypt)))
    (lambda (func)
      "Return a pointer to symbol FUNC in libgcrypt."
      (dynamic-func func lib))))

(define gcrypt-version
  ;; According to the manual, this function must be called before any other,
  ;; and it's not clear whether it can be called more than once.  So call it
  ;; right here from the top level.
  (let* ((ptr     (libgcrypt-func "gcry_check_version"))
         (proc    (pointer->procedure '* ptr '(*)))
         (version (pointer->string (proc %null-pointer))))
    (lambda ()
      "Return the version number of libgcrypt as a string."
      version)))

;;; gcrypt.scm ends here