clear_obj — 从 HALCON 数据库中删除图标对象。
clear_obj(Objects : : : )
clear_obj deletes iconic objects, which are no longer
needed, from the HALCON database. It should be noted that
clear_obj is the only way to delete objects from the
database, and hence to reclaim their memory, in HALCON/C. In all
other HALCON language interfaces, clear_obj must
not be used because objects are destroyed automatically through
appropriate destructors.
Images and regions are normally used by several iconic objects at the same time (uses less memory!). This has the consequence that a region or an image is only deleted if all objects using it have been deleted.
The operator reset_obj_db can be used to reset the system
and clear all remaining iconic objects.
For a short description of the iconic objects that are available in HALCON see the introduction of chapter 对象.
Regarding the use of local variables in HALCON/C: When exiting a subroutine, the local variables are deleted, but the HALCON database is not updated. To update the database and thus free the memory, you must explicitly clear the local objects from the database before exiting the subroutine.
Objects (input_object) object(-array) → object
Objects to be deleted.
clear_obj returns 2 (
H_MSG_TRUE)
if all objects are contained in
the HALCON database. If not all objects are valid (e.g., already
cleared), an exception is raised, which also clears all valid objects.
The operator set_check(::'~clear':)
can be used to suppress the raising of this exception. If the input is
empty the behavior can be set via
set_system(::'no_object_result',<Result>:).
If necessary, an exception is raised.
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