Hi everybody Are there any type of files that is required by io.loaddata or/and buffers.assign ? The following code works pretty well if there is no compilation problem by g++. But it fails, i.e. \typebuffer[Mybuffer], does not produce anything if g++ fails (due to some errors in the cpp) I have checked that err.cpp is well and truly created when g++ fails. \startluacode io.savedata("complx.h",buffers.getcontent("MyBuffer1")) io.savedata("complx.cpp",buffers.getcontent("MyBuffer2")) io.savedata("testcomplx.cpp",buffers.getcontent("MyBuffer3")) local l=os.execute("g++ -O3 -Wall -o testcomplx testcomplx.cpp complx.cpp 2> err.cpp") if l==0 then os.execute("./testcomplx > testcomplx.tmp") buffers.assign("MyBuffer",io.loaddata("testcomplx.tmp")) else buffers.assign("Mybuffer",io.open("err.cpp","r")) end \stopluacode Many thanks Thierry