SVGHMI: JsonTable now use intermediate variables again to address JSON data without duplicating code or referencing. Using intermediate variables also alows to check for availability of data and stop evaluating early if data is missing. Finally added complete roundtrip example to illustrate use of JSonTable to display "alarms" collected in python from changes on PLC boolean variables.
#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# See COPYING.Runtime file for copyrights details.
#
from __future__ import absolute_import
from ctypes import CDLL, RTLD_GLOBAL, pointer, c_int, POINTER, c_char, create_string_buffer
def TryPreloadXenomai():
"""
Xenomai 3 (at least for version <= 3.0.6) do not handle properly dlclose
of shared objects whose dlopen did trigger xenomai_init.
As a workaround, this pre-loads xenomai libraries that need to be
initialized and call xenomai_init once for all.
Xenomai auto init of libs MUST be disabled (see --auto-init-solib in xeno-config)
"""
try:
for name in ["cobalt", "modechk", "copperplate", "alchemy"]:
globals()[name] = CDLL("lib"+name+".so", mode=RTLD_GLOBAL)
cobalt.xenomai_init(pointer(c_int(0)), pointer((POINTER(c_char)*2)(create_string_buffer("prog_name"), None)))
except Exception:
pass