typedef struct x1f4_datatype_type {
const char *name;
int (*flat) (void *, void *, void **), (*line) (void *, void *, void **),
(*link) (void *, void *, void **), (*shut) (void *, void *, void **),
type;
unsigned size;
void *context;
} x1f4_datatype_type;
The x1f4_datatype_type record describes an application defined type.
namename is the type name, i.e. the string that introduces declarations
of variable of this application defined type.
flatflat field is the address of the routine finalizing data (variables
that is) when such data comes out of use (when data declaration scope expires
for an instance). If no such finalizing routine is required flat should
be set to NULL. When called, the routine is supplied the application
defined types context (some pointer provided by the application to the
executable program representation contructor for exactly this purpose), this
very type context (the context field in this very record) and the
address at which data (the variable) is stored (in turn, a pointer (void
*) itself).
See struct x1f4_c1_type.
The method needs to set the data to pre-initialized value before completion (for the pre-initializing routine will not be called again).
The flat method is used for finalizing data only in normal program
execution, not after a program execution interruption. The shut method
finalizes data after program execution interruptions.
lineline field is the address of the routine initializing data
(variables that is) when such data comes into use (when declaration scope is
entered for an instance). If no such initializing routine is required
line should be set to NULL. When called, the routine is supplied
the application defined types context (some pointer provided by the application
to the executable program representation contructor for exactly this purpose),
this very type context (the context field in this very record) and the
address at which data (the variable) is stored (in turn, a pointer (void
*) itself).
See struct x1f4_c1_type.
linklink field is the address of the routine pre-initializing data
(variables that is) when memory is allocated for such data. The need for such
routine comes from the emergency program execution cleaner inability to
distinguish between proper initialized (via line routine) and
uninitialized data. The emergency program execution cleaner is the part of the
interpreters that is called when some interpreted program or part of program
failed execution and the initialized data has to be finalized. The cleaner
will not make distinction between data initialized and uninitialized and will
call the finalizer (the shut routine) for all data. The link may
set data to some value (like NULL for pointers) to indicate that data
has never been (successfully) initialized. The flat and shut
routines may like to set thenselves data to such pre-initialized value once
they finalize data, since link will not be called again, not if the data
is reallocated. If no such pre-initializing routine is required link
should be set to NULL. When called, the routine is supplied the
application defined types context (some pointer provided by the application to
the executable program representation contructor for exactly this purpose),
this very type context (the context field in this very record) and the
address at which data (the variable) is stored (in turn, a pointer (void
*) itself).
See struct x1f4_c1_type.
shutshut field is the address of the routine finalizing data (variables
that is) after a program execution interrupt. If no such finalizing routine is
required shut should be set to NULL. When called, the routine is
supplied the application defined types context (some pointer provided by the
application to the executable program representation contructor for exactly
this purpose), this very type context (the context field in this very
record) and the address at which data (the variable) is stored (in turn, a
pointer (void *) itself).
See struct x1f4_c1_type.
See Execution Completion Cleanup.
The method needs to set the data to pre-initialized value before completion (for the pre-initializing routine will not be called again).
The shut method does not finalize data during normal program execution.
The flat method does.
typetype field is the type id, i.e. the number that will identify run
time data as belonging to this application defined type.
sizesize field is the type name length, i.e. the number of characters
(not including the terminal null) making up the type name.
contextcontext field is the context of this very type definition. It is
passed as argument to type specific methods (flat, line,
link and shut in this very definition) and not used otherwise.