https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87088
--- Comment #13 from miltonkbenjamin <miltonkbenjamin at verizon dot net> --- (In reply to Jonathan Wakely from comment #12) > (In reply to miltonkbenjamin from comment #11) > > > C:\parser>g++ -include iostream.h -Xpreprocessor "FlexLexer.h" > > > lex1.yy.cc > > You're STILL passing a filename as the argument to -Xpreprocessor. > > What part of my comments do you not understand? Hi Jonathan, I tried what you suggested, and it failed as per comment 10 here. If you can send me an email address, I can send you the files (and for a fee?) see if you can get it working. I installed win_flex, win_bison and g++ on dozens of Win 7 PCS and it worked each and every time. I currently have a Win 10 PC and it failed on 3 Win 10 PC's I have access to. Thanks for your support, Milt Benjamin