MiKTeX: pdftex -trace=...,...,... ???

Hello,

I try the -trace option of the compilers (etex , pdfTeX) but
nothing seems to happen.


I hoped the trace and tracefile variables would output something !


My miktex.ini file is :

% ---------------------------------------------------------------------
max_print_line=90 ; width of the .log lines

error_line=90 ; width of the error .log lines (<= max_print_line)
half_error_line=75 ; width of the first error .log lines ( >=30 and <= error_line-15 )

trace=access,config,core,curl,dib,dvibitmap,dvicolor,dvifile,dvigc,dvihypertex,dvipage,dvipkbitmap,dvipkchar,dvipkfont,dvisearch,dvitfm,dvivfchar,dvivfont,env,error,extractor,files,filesearch,fndb,fontinfo,mem,mmap,mpm,mtprint,packages,process,tempfile,time,values,yap
tracefile=<some file>
% ---------------------------------------------------------------------


By the way, I found how to change the width of the .log lines :
-max-print-line = <Number of characters>

Thanks if you have any clue about trace and tracefile.
I read several MiKTeX manuals for different versions without success... too bad

.