ChnPropSet from GPI-Dll

Question

Hey!
I think this would have been asked before, but I could not find the answer.. so..
I am creating a Waveform-Channel from a GPI-dll. Transferring the data works fine, but now I am stuck at the offset and increment parameters which I cannot set. Following some examples here, I have created the following code:
#import "DIAdem.tlb" no_namespace
::CoInitialize(NULL);
ITOCommandPtr pITOCommandT;
pITOCommandT.CreateInstance("DIAdem.ToCommand");
pITOCommandT->CmdExecuteSync(_variant_t("Call ChnPropSet(10, \"wf_start_offset\", 1.734)"));
::CoUninitialize();
Actually, the 10 as a channel number is hardcoded here, in the program, I am getting it when creating the channel, via
hDataObjTData = hDataObjChannelGet( szDataObjNameT,f_size_,1,1);
int chn = hDataObjTData;
And then chn contains the channel number. Don't know if that is the way to go, but it's the only solution I have found quickly..
Anyhow, the CmdExecuteSync-call always fails. I have tried it with call, without call, " and ' as quotation marks, and also with and without brackets.
What have I missed, how does it work?
Many thx!!

Answer 1

Actually, after trying this
//pITOCommandT->CmdExecuteSync(_variant_t("Call ChnPropSet(10, \"wf_start_offset\", 1.734)"));
//pITOCommandT->CmdExecuteSync(_variant_t("Call ChnPropSet 10, \"wf_start_offset\", 1.734"));
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet(10, \"wf_start_offset\", 1.734)"));
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet 10, \"wf_start_offset\", 1.734"));
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet 10 \"wf_start_offset\" 1.734"));
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet 10 'wf_start_offset' 1.734"));
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet(10, \"wf_start_offset\", 2)"));
//pITOCommandT->CmdExecuteSync(_variant_t("Call ChnPropSet(10, \"wf_start_offset\", \"1.734\")"));
//pITOCommandT->CmdExecuteSync(_variant_t("Call ChnPropSet 10, \"wf_start_offset\", \"1.734\""));
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet(10, \"wf_start_offset\", \"1.734\")")); // <- good
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet 10, \"wf_start_offset\", \"1.734\"")); // <- good
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet 10 \"wf_start_offset\" \"1.734\""));
//pITOCommandT->CmdExecuteSync(_variant_t("ChnPropSet 10 'wf_start_offset' '1.734'"));
I found out that the last parameter also needs quotation marks. Did I miss this in the documentation??
I already have a new problem though: how can I tell DIAdem that this is a waveform channel?
This one, it does not like:
_snprintf(temp, sizeof(temp), "ChnPropSet %i, \"waveform\", \"Yes\"", chn);
pITOCommandT->CmdExecuteSync(_variant_t(temp));
, just like these lines of code
// wf_samples
_snprintf(temp, sizeof(temp), "ChnPropSet %i, \"wf_samples\", \"%i\"", chn, length);
pITOCommandT->CmdExecuteSync(_variant_t(temp));
// wf_time_pref
_snprintf(temp, sizeof(temp), "ChnPropSet %i, \"wf_time_pref\", \"relative\"", chn);
So, again, I don't know what to do..
Any ideas?