Segmentation fault when use GroupObject::value write string to bus.

[killerlife]

Hi,

I am try to use GroupObject::value write string to bus. My sample code are below:

#define GO_ZONE1_TITLE		knx.getGroupObject(49)
GO_ZONE1_TITLE.dataPointType(DPT_String_ASCII);
GO_ZONE1_TITLE.value(t.c_string());

It got segmentation fault when call GO_ZONE1_TITLE.value(t.c_string());

The following is backtrace from gdb:
(gdb) bt
#0 0x00000055557b56e8 in unsigned8ToPayload (payload=0x0, payload_length=37, index=0, value=228 '\344', mask=255 '\377') at /home/le/MRA/source/HS.PA/knx/knx/dptconvert.cpp:1909
#1 0x00000055557b3e38 in valueToBusValueString (value=..., payload=0x0, payload_length=37, datatype=...) at /home/le/MRA/source/HS.PA/knx/knx/dptconvert.cpp:1341
#2 0x00000055557b0dec in KNX_Encode_Value (value=..., payload=0x0, payload_length=37, datatype=...) at /home/le/MRA/source/HSr.PA/knx/knx/dptconvert.cpp:260
#3 0x00000055557b6e70 in GroupObject::valueNoSend (this=0x7fe4001c40, value=..., type=...) at /home/le/MRA/source/HS.PA/knx/knx/group_object.cpp:308
#4 0x00000055557b6c24 in GroupObject::value (this=0x7fe4001c40, value=..., type=...) at /home/le/MRA/source/HS.PA/knx/knx/group_object.cpp:247
#5 0x00000055557b6dc8 in GroupObject::value (this=0x7fe4001c40, value=...) at /home/le/MRA/source/HS.PA/knx/knx/group_object.cpp:290
#6 0x0000005555796b3c in Knx_Srv::SetZoneTitle (this=0x555659e230 <GetKnx_Srv()::gKnx_Srv>, zone=1 '\002', title="一無所有(是否我真的一無所有)") at /home/le/MRA/source/HS.PA/knx_srv.cpp:500`

It seems _data is a nullptr. I check the group_object.cpp, there is not memory alloc initalization code in the source. Maybe it's a bug.