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16e58dc901
The critical omission from the GClosure documentation is that you need to call g_closure_set_marshal() when implementing a custom GClosure. Signed-off-by: Philip Withnall <withnall@endlessm.com> Reviewed-by: nobody
318 lines
11 KiB
C
318 lines
11 KiB
C
/* GObject - GLib Type, Object, Parameter and Signal Library
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* Copyright (C) 2000-2001 Red Hat, Inc.
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* Copyright (C) 2005 Imendio AB
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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
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* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __G_CLOSURE_H__
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#define __G_CLOSURE_H__
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#if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
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#error "Only <glib-object.h> can be included directly."
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#endif
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#include <gobject/gtype.h>
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G_BEGIN_DECLS
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/* --- defines --- */
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/**
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* G_CLOSURE_NEEDS_MARSHAL:
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* @closure: a #GClosure
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*
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* Check if the closure still needs a marshaller. See g_closure_set_marshal().
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*
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* Returns: %TRUE if a #GClosureMarshal marshaller has not yet been set on
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* @closure.
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*/
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#define G_CLOSURE_NEEDS_MARSHAL(closure) (((GClosure*) (closure))->marshal == NULL)
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/**
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* G_CLOSURE_N_NOTIFIERS:
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* @cl: a #GClosure
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*
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* Get the total number of notifiers connected with the closure @cl.
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* The count includes the meta marshaller, the finalize and invalidate notifiers
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* and the marshal guards. Note that each guard counts as two notifiers.
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* See g_closure_set_meta_marshal(), g_closure_add_finalize_notifier(),
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* g_closure_add_invalidate_notifier() and g_closure_add_marshal_guards().
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*
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* Returns: number of notifiers
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*/
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#define G_CLOSURE_N_NOTIFIERS(cl) (((cl)->n_guards << 1L) + \
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(cl)->n_fnotifiers + (cl)->n_inotifiers)
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/**
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* G_CCLOSURE_SWAP_DATA:
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* @cclosure: a #GCClosure
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*
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* Checks whether the user data of the #GCClosure should be passed as the
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* first parameter to the callback. See g_cclosure_new_swap().
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*
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* Returns: %TRUE if data has to be swapped.
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*/
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#define G_CCLOSURE_SWAP_DATA(cclosure) (((GClosure*) (cclosure))->derivative_flag)
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/**
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* G_CALLBACK:
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* @f: a function pointer.
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*
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* Cast a function pointer to a #GCallback.
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*/
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#define G_CALLBACK(f) ((GCallback) (f))
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/* -- typedefs --- */
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typedef struct _GClosure GClosure;
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typedef struct _GClosureNotifyData GClosureNotifyData;
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/**
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* GCallback:
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*
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* The type used for callback functions in structure definitions and function
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* signatures. This doesn't mean that all callback functions must take no
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* parameters and return void. The required signature of a callback function
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* is determined by the context in which is used (e.g. the signal to which it
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* is connected). Use G_CALLBACK() to cast the callback function to a #GCallback.
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*/
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typedef void (*GCallback) (void);
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/**
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* GClosureNotify:
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* @data: data specified when registering the notification callback
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* @closure: the #GClosure on which the notification is emitted
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*
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* The type used for the various notification callbacks which can be registered
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* on closures.
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*/
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typedef void (*GClosureNotify) (gpointer data,
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GClosure *closure);
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/**
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* GClosureMarshal:
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* @closure: the #GClosure to which the marshaller belongs
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* @return_value: (nullable): a #GValue to store the return
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* value. May be %NULL if the callback of @closure doesn't return a
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* value.
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* @n_param_values: the length of the @param_values array
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* @param_values: (array length=n_param_values): an array of
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* #GValues holding the arguments on which to invoke the
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* callback of @closure
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* @invocation_hint: (nullable): the invocation hint given as the
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* last argument to g_closure_invoke()
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* @marshal_data: (nullable): additional data specified when
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* registering the marshaller, see g_closure_set_marshal() and
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* g_closure_set_meta_marshal()
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*
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* The type used for marshaller functions.
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*/
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typedef void (*GClosureMarshal) (GClosure *closure,
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GValue *return_value,
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guint n_param_values,
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const GValue *param_values,
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gpointer invocation_hint,
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gpointer marshal_data);
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/**
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* GVaClosureMarshal:
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* @closure: the #GClosure to which the marshaller belongs
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* @return_value: (nullable): a #GValue to store the return
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* value. May be %NULL if the callback of @closure doesn't return a
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* value.
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* @instance: (type GObject.TypeInstance): the instance on which the closure is
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* invoked.
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* @args: va_list of arguments to be passed to the closure.
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* @marshal_data: (nullable): additional data specified when
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* registering the marshaller, see g_closure_set_marshal() and
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* g_closure_set_meta_marshal()
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* @n_params: the length of the @param_types array
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* @param_types: (array length=n_params): the #GType of each argument from
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* @args.
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*
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* This is the signature of va_list marshaller functions, an optional
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* marshaller that can be used in some situations to avoid
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* marshalling the signal argument into GValues.
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*/
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typedef void (* GVaClosureMarshal) (GClosure *closure,
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GValue *return_value,
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gpointer instance,
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va_list args,
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gpointer marshal_data,
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int n_params,
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GType *param_types);
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/**
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* GCClosure:
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* @closure: the #GClosure
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* @callback: the callback function
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*
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* A #GCClosure is a specialization of #GClosure for C function callbacks.
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*/
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typedef struct _GCClosure GCClosure;
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/* --- structures --- */
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struct _GClosureNotifyData
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{
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gpointer data;
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GClosureNotify notify;
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};
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/**
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* GClosure:
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* @in_marshal: Indicates whether the closure is currently being invoked with
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* g_closure_invoke()
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* @is_invalid: Indicates whether the closure has been invalidated by
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* g_closure_invalidate()
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*
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* A #GClosure represents a callback supplied by the programmer.
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*/
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struct _GClosure
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{
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/*< private >*/
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volatile guint ref_count : 15;
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/* meta_marshal is not used anymore but must be zero for historical reasons
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as it was exposed in the G_CLOSURE_N_NOTIFIERS macro */
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volatile guint meta_marshal_nouse : 1;
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volatile guint n_guards : 1;
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volatile guint n_fnotifiers : 2; /* finalization notifiers */
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volatile guint n_inotifiers : 8; /* invalidation notifiers */
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volatile guint in_inotify : 1;
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volatile guint floating : 1;
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/*< protected >*/
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volatile guint derivative_flag : 1;
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/*< public >*/
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volatile guint in_marshal : 1;
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volatile guint is_invalid : 1;
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/*< private >*/ void (*marshal) (GClosure *closure,
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GValue /*out*/ *return_value,
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guint n_param_values,
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const GValue *param_values,
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gpointer invocation_hint,
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gpointer marshal_data);
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/*< protected >*/ gpointer data;
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/*< private >*/ GClosureNotifyData *notifiers;
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/* invariants/constraints:
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* - ->marshal and ->data are _invalid_ as soon as ->is_invalid==TRUE
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* - invocation of all inotifiers occours prior to fnotifiers
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* - order of inotifiers is random
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* inotifiers may _not_ free/invalidate parameter values (e.g. ->data)
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* - order of fnotifiers is random
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* - each notifier may only be removed before or during its invocation
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* - reference counting may only happen prior to fnotify invocation
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* (in that sense, fnotifiers are really finalization handlers)
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*/
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};
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/* closure for C function calls, callback() is the user function
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*/
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struct _GCClosure
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{
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GClosure closure;
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gpointer callback;
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};
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/* --- prototypes --- */
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GLIB_AVAILABLE_IN_ALL
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GClosure* g_cclosure_new (GCallback callback_func,
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gpointer user_data,
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GClosureNotify destroy_data);
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GLIB_AVAILABLE_IN_ALL
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GClosure* g_cclosure_new_swap (GCallback callback_func,
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gpointer user_data,
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GClosureNotify destroy_data);
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GLIB_AVAILABLE_IN_ALL
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GClosure* g_signal_type_cclosure_new (GType itype,
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guint struct_offset);
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/* --- prototypes --- */
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GLIB_AVAILABLE_IN_ALL
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GClosure* g_closure_ref (GClosure *closure);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_sink (GClosure *closure);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_unref (GClosure *closure);
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/* intimidating */
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GLIB_AVAILABLE_IN_ALL
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GClosure* g_closure_new_simple (guint sizeof_closure,
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gpointer data);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_add_finalize_notifier (GClosure *closure,
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gpointer notify_data,
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GClosureNotify notify_func);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_remove_finalize_notifier (GClosure *closure,
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gpointer notify_data,
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GClosureNotify notify_func);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_add_invalidate_notifier (GClosure *closure,
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gpointer notify_data,
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GClosureNotify notify_func);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_remove_invalidate_notifier (GClosure *closure,
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gpointer notify_data,
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GClosureNotify notify_func);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_add_marshal_guards (GClosure *closure,
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gpointer pre_marshal_data,
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GClosureNotify pre_marshal_notify,
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gpointer post_marshal_data,
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GClosureNotify post_marshal_notify);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_set_marshal (GClosure *closure,
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GClosureMarshal marshal);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_set_meta_marshal (GClosure *closure,
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gpointer marshal_data,
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GClosureMarshal meta_marshal);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_invalidate (GClosure *closure);
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GLIB_AVAILABLE_IN_ALL
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void g_closure_invoke (GClosure *closure,
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GValue /*out*/ *return_value,
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guint n_param_values,
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const GValue *param_values,
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gpointer invocation_hint);
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/* FIXME:
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OK: data_object::destroy -> closure_invalidate();
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MIS: closure_invalidate() -> disconnect(closure);
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MIS: disconnect(closure) -> (unlink) closure_unref();
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OK: closure_finalize() -> g_free (data_string);
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random remarks:
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- need marshaller repo with decent aliasing to base types
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- provide marshaller collection, virtually covering anything out there
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*/
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GLIB_AVAILABLE_IN_ALL
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void g_cclosure_marshal_generic (GClosure *closure,
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GValue *return_gvalue,
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guint n_param_values,
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const GValue *param_values,
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gpointer invocation_hint,
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gpointer marshal_data);
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GLIB_AVAILABLE_IN_ALL
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void g_cclosure_marshal_generic_va (GClosure *closure,
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GValue *return_value,
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gpointer instance,
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va_list args_list,
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gpointer marshal_data,
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int n_params,
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GType *param_types);
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G_END_DECLS
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#endif /* __G_CLOSURE_H__ */
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