Hello, \def\show{Hello World} \pdfprimitive\show\relax I would expect that the primitive \show (not the macro) is executed and shows \relax. Instead I get an error (pdfTeX 1.40.3): ! Undefined control sequence. l.2 \pdfprimitive\show Did I misunderstood \pdfprimitive? Yours sincerely Heiko <oberdiek at uni-freiburg.de> --