read_structure_by_name with REFERENCE TO variables in structure on plc

[Planeerbeer]

Dear devs,

I am fetching structs from my PLC that contain variables that are REFERENCE TO LREAL (for example):

I have an array of these structs i want to read using the pyads.connection.read_structure_by_name method. my python structure def and code are attahed below :

import pyads
from config.targets.target_configs import VBox

structure_def = (
    ("nSignalIndex", pyads.PLCTYPE_UINT, 1),
    ("fValue", pyads.PLCTYPE_LREAL, 1),
    ("sModuleName", pyads.PLCTYPE_STRING, 1),
    ("sSignalName", pyads.PLCTYPE_STRING, 1, 255),
    ("sDataUnit", pyads.PLCTYPE_STRING, 1),
    ("sSignalInfo", pyads.PLCTYPE_STRING, 1, 255),
    ("sSignalPath", pyads.PLCTYPE_STRING, 1, 255),
)

#   fetches a single struct in the array of structs
# returns NaN for the reference variable
get_struct = VBox.connection.read_structure_by_name(
    data_name="GVL_MachineGlobals.gSignalRegistry_SingletonCore.aSignalInfo[2]",
    structure_def=structure_def,
)

#   fetches multiple structs in the array of structs
# returns NaN for the reference variable
array_structs = VBox.connection.read_structure_by_name(
    data_name="GVL_MachineGlobals.gSignalRegistry_SingletonCore.aSignalInfo",
    structure_def=structure_def,
    array_size=3,
)

# fetches the NaN value directly
fValue = VBox.connection.read_by_name(
    data_name="GVL_MachineGlobals.gSignalRegistry_SingletonCore.aSignalInfo[2].fValue",
    plc_datatype=pyads.PLCTYPE_LREAL,
)
for key, item in get_struct.items():
    print(f"{key}: {item}")
print("done")

If i now read this structure, all variables are correctly read, except the variables of type REFERENCE, they return NaN

If i manually read this REFERENCE variable directly using the pyads.connection.read_by_name method, it does correctly read the value, but if i read it within a structure_def, it gives me NaN

I hope the problem statement is clear like this.

Many thanks for looking into my issue <3

[chrisbeardy]

Interesting never thought about pointers and references in the initial implementation, will have to think about this