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f5710d53b1
SCM_SMOB_FLAGS and SCM_SET_SMOB_FLAGS instead of accessing the zeroth word directly. Use SCM_SMOB_PREDICATE as appropriate.
93 lines
3.5 KiB
C
93 lines
3.5 KiB
C
/* classes: h_files */
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#ifndef SCM_FLUIDS_H
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#define SCM_FLUIDS_H
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/* Copyright (C) 1996,2000,2001 Free Software Foundation, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "libguile/__scm.h"
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#include "libguile/root.h"
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#include "libguile/vectors.h"
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/* Fluids.
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Fluids are objects of a certain type (a smob) that can hold one SCM
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value per dynamic root. That is, modifications to this value are
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only visible to code that executes within the same dynamic root as
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the modifying code. When a new dynamic root is constructed, it
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inherits the values from its parent. Because each thread executes
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in its own dynamic root, you can use fluids for thread local
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storage.
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Each fluid is identified by a small integer. This integer is used
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to index a vector that holds the values of all fluids. Each root
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has its own vector.
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Currently, you can't get rid a certain fluid if you don't use it
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any longer. The slot that has been allocated for it in the fluid
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vector will not be reused for other fluids. Therefore, only use
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SCM_MAKE_FLUID or its Scheme variant `make-fluid' in initialization
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code that is only run once. Nevertheless, it should be possible to
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implement a more lightweight version of fluids on top of this basic
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mechanism. */
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SCM_API scm_t_bits scm_tc16_fluid;
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#define SCM_FLUIDP(x) (SCM_SMOB_PREDICATE (scm_tc16_fluid, (x)))
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#define SCM_FLUID_NUM(x) (SCM_CELL_WORD_1 (x))
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/* The fastest way to acces/modify the value of a fluid. These macros
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do no error checking at all. You should only use them when you know
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that the relevant fluid already exists in the current dynamic root.
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The easiest way to ensure this is to execute a SCM_FLUID_SET_X in the
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topmost root, for example right after SCM_MAKE_FLUID in your
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SCM_INIT_MUMBLE routine that gets called from SCM_BOOT_GUILE_1. The
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first argument is the index number of the fluid, obtained via
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SCM_FLUID_NUM, not the fluid itself. */
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#define SCM_FAST_FLUID_REF(n) (SCM_VELTS(scm_root->fluids)[n])
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#define SCM_FAST_FLUID_SET_X(n, val) (SCM_VELTS(scm_root->fluids)[n] = val)
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SCM_API SCM scm_make_fluid (void);
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SCM_API SCM scm_fluid_p (SCM fl);
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SCM_API SCM scm_fluid_ref (SCM fluid);
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SCM_API SCM scm_fluid_set_x (SCM fluid, SCM value);
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SCM_API SCM scm_c_with_fluids (SCM fluids, SCM vals,
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SCM (*cproc)(void *), void *cdata);
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SCM_API SCM scm_c_with_fluid (SCM fluid, SCM val,
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SCM (*cproc)(void *), void *cdata);
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SCM_API SCM scm_with_fluids (SCM fluids, SCM vals, SCM thunk);
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SCM_API SCM scm_with_fluid (SCM fluid, SCM val, SCM thunk);
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SCM_API void scm_frame_fluid (SCM fluid, SCM value);
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SCM_API SCM scm_i_make_initial_fluids (void);
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SCM_API void scm_i_copy_fluids (scm_root_state *);
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SCM_API void scm_init_fluids (void);
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#endif /* SCM_FLUIDS_H */
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/*
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Local Variables:
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c-file-style: "gnu"
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End:
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*/
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