Re: [libvirt] [PATCH V2 2/4] src/xenconfig: Xen-xl parser

David kiarie wrote: I looked at coreutils following Eric's suggestion, but didn't notice any use of flex. I went back to the automake documented approach [1] and peeked at the resulting generated files. src/Makefile.in contains LEX_OUTPUT_ROOT = lex.yy LEXCOMPILE = $(LEX) $(AM_LFLAGS) $(LFLAGS) .l.c: $(AM_V_LEX)$(am__skiplex) $(SHELL) $(YLWRAP) $< $(LEX_OUTPUT_ROOT).c $@ -- $(LEXCOMPILE) which during an actual make produces /bin/sh ../build-aux/ylwrap xenconfig/libxlu_disk_l.l lex.yy.c xenconfig/libxlu_disk_l.c -- flex But later the build fails with CC xenconfig/libvirt_xenconfig_la-xen_xl.lo xenconfig/xen_xl.c:28:27: fatal error: libxlu_disk_l.h: No such file or directory #include "libxlu_disk_l.h" Which is the problem I mentioned earlier in the thread about flex not generating a header file. I naively tried hacking '--header-file' into AM_LFLAGS (e.g. AM_LFLAGS=--header-file=$*.h), but flex wasn't happy with that make[2]: Entering directory `libvirt/src' /bin/sh ../build-aux/ylwrap xenconfig/libxlu_disk_l.l lex.yy.c xenconfig/libxlu_disk_l.c -- flex --header-file=xenconfig/libxlu_disk_l.h flex: fatal internal error, freopen(headerfilename) failed I banged my head on this for a while but couldn't find a resolution :-/. The alternate approach is to use hand-crafted rules in src/Makefile.am, as you've done. I'd prefer something a bit more generic like %.c %.h:: %.l @rm -f $*.[ch] $(AM_V_GEN)$(LEX) --header-file=$*.h --outfile=$*.c $< Which does work but has the two issues we discussed earlier: - warning flags need relaxed when compiling the generated files - generated files need to be excluded from syntax-check The second issue is trivial, and although not obvious to me, I think there are several devs on the list that can give hints. Regards, Jim [1] http://www.gnu.org/software/automake/manual/html_node/Yacc-and-Lex.html