Thanks for the close observation. The typo is only in composing this post however it isn't there in my actual code.
Well, I realized a solution for my problem which I would like to share. However this has pushed me into another problem which happens to be the continued discussion.
We can edit the parameter(say lengthParam) values in two ways.
1) cdfgData->lengthParam->defvalue =33
2) cellObj = ddGetObj( "myLib" "myCell" nil nil nil "a")
bcCdf = cdfGetBaseCellCDF( cellObj)
lengthParam = nth( i bcCdf->parameters) ; Assuming ith value is lengthParam
lengthParam->defValue = 33
The first one would issue the mentioned Warning message which I had interpreted wrongly before and the second one wouldn't issue the warning message. So, going by (2) method solved my problem.
a) When I attach a callback message to the same parameter which happens to be a dialogBox to lengthParam->callback, it fails !!
e.g: lengthParam->callback = "hiDisplayAppDBox(?name 'f ?dboxBanner \"Warning\" ?dboxText \"The defValue is being assigned back\" ?dialogType hicWarningDialog ?dialogStyle 'modal ?buttonLayout 'OKCancel ) "
It is leading to segmentation faults !!
b) If I were to attach a callback which is a simple print statement etc, the results are fine.
e.g: lengthParam->callback = "printf(\" I am assigning the value back to default\")"