libguile/fluids.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_FLUIDS_H
   4 #define SCM_FLUIDS_H
   5
   6 /* Copyright (C) 1996,2000,2001, 2006, 2008 Free Software Foundation, Inc.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 \f
  24
  25 #include "libguile/__scm.h"
  26 #include "libguile/root.h"
  27 #include "libguile/vectors.h"
  28
  29 /* Fluids.
  30
  31    Fluids are objects of a certain type (a smob) that can hold one SCM
  32    value per dynamic state.  That is, modifications to this value are
  33    only visible to code that executes with the same dynamic state as
  34    the modifying code.  When a new dynamic state is constructed, it
  35    inherits the values from its parent.  Because each thread executes
  36    with its own dynamic state, you can use fluids for thread local
  37    storage.
  38
  39    Each fluid is identified by a small integer.  This integer is used
  40    to index a vector that holds the values of all fluids.  A dynamic
  41    state consists of this vector, wrapped in a smob so that the vector
  42    can grow.
  43  */
  44
  45 /* The fastest way to acces/modify the value of a fluid.  These macros
  46    do no error checking at all.  The first argument is the index
  47    number of the fluid, obtained via SCM_FLUID_NUM, not the fluid
  48    itself.  You must make sure that the fluid remains protected as
  49    long you use its number since numbers of unused fluids are reused
  50    eventually.
  51 */
  52
  53 SCM_API SCM scm_make_fluid (void);
  54 SCM_API int scm_is_fluid (SCM obj);
  55 SCM_API SCM scm_fluid_p (SCM fl);
  56 SCM_API SCM scm_fluid_ref (SCM fluid);
  57 SCM_API SCM scm_fluid_set_x (SCM fluid, SCM value);
  58
  59 SCM_API SCM scm_c_with_fluids (SCM fluids, SCM vals,
  60                                SCM (*cproc)(void *), void *cdata);
  61 SCM_API SCM scm_c_with_fluid (SCM fluid, SCM val,
  62                               SCM (*cproc)(void *), void *cdata);
  63 SCM_API SCM scm_with_fluids (SCM fluids, SCM vals, SCM thunk);
  64 SCM_API SCM scm_with_fluid (SCM fluid, SCM val, SCM thunk);
  65
  66 SCM_API void scm_dynwind_fluid (SCM fluid, SCM value);
  67
  68 SCM_API SCM scm_make_dynamic_state (SCM parent);
  69 SCM_API SCM scm_dynamic_state_p (SCM obj);
  70 SCM_API int scm_is_dynamic_state (SCM obj);
  71 SCM_API SCM scm_current_dynamic_state (void);
  72 SCM_API SCM scm_set_current_dynamic_state (SCM state);
  73 SCM_API void scm_dynwind_current_dynamic_state (SCM state);
  74 SCM_API void *scm_c_with_dynamic_state (SCM state,
  75                                         void *(*func)(void *), void *data);
  76 SCM_API SCM scm_with_dynamic_state (SCM state, SCM proc);
  77
  78 SCM_INTERNAL SCM scm_i_make_initial_dynamic_state (void);
  79
  80 SCM_INTERNAL void scm_fluids_prehistory (void);
  81 SCM_INTERNAL void scm_init_fluids (void);
  82
  83 #endif  /* SCM_FLUIDS_H */
  84
  85 /*
  86   Local Variables:
  87   c-file-style: "gnu"
  88   End:
  89 */