Use skill to export gdsII

HI:

I want to export GDS from the layout. I know that it can be done by using Virtuoso CIW ( File-->Export-->stream). But I need to use the skill to done it . I use virtuoso IC6.1.7

My code is :

procedure(strmout_gds()

cellid = geGetEditCellView()
printf("cellid %L \n" cellid)

thisLibName = cellid->libName
printf("thisLibName %L \n" thisLibName)

thisCellName = cellid->cellName
printf("thisCellName %L \n" thisCellName)

streamOutKeys = ncons(nil)

streamOutKeys->runDir = "."

streamOutKeys->libName = thisLibName

streamOutKeys->primaryCell = thisCellName

streamOutKeys->viewName = "layout"

streamOutKeys->scale = 0.001

streamOutKeys->units = "micron"

streamOutKeys->libVersion = "5.0"

streamOutKeys->errFile = "PIPO.LOG"

streamOutKeys->outFile= strcat("/home1st/art83420/NCSU-FreePDK15-1.2_final/FreePDK15/cdslib" thisCellName ".calibre.gds")

id = ipcBeginProcess("cd /home1st/art83420/NCSU-FreePDK15-1.2_final/FreePDK15/cdslib; source .bashrc; pipo strmout xstrmOut.templt")
printf("id %L\n" id)

ipcWait(id)

)

I found examples at the following URL
http://www.dayexie.com/detail2035097.html

My problem is the code can run and doesn't have error. But can't generate gds 

Have anyone can tell me where is the problem or how to write the code 

thanks