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| author | Akim Demaille <akim.demaille@gmail.com> | 2020-05-03 09:51:18 +0200 |
|---|---|---|
| committer | Akim Demaille <akim.demaille@gmail.com> | 2020-05-03 10:32:32 +0200 |
| commit | 392f3caef6c3be1496b2e7d8377db111ca1b8e5b (patch) | |
| tree | 941c95eec7aad6adade35771a00f341003a4f19d | |
| parent | ccaa8e29f92170a92ef2d38128d122aec59e6dbe (diff) | |
| download | bison-392f3caef6c3be1496b2e7d8377db111ca1b8e5b.tar.gz | |
examples: beware of the portability of flex --header-file
The option --header was introduced in version 2.5.6.
The option --header-file was introduced in version 2.6.4.
Reported by Bruno Haible.
https://lists.gnu.org/r/bug-bison/2020-05/msg00013.html
So use --header, and do bother with versions that don't support it.
* m4/flex.m4: Check whether flex supports --header.
* configure.ac (FLEX_WORKS, FLEX_CXX_WORKS): Set to false if it doesn't.
* * examples/c/reccalc/local.mk, examples/c/reccalc/Makefile:
Use --header rather than --header-file.
| -rw-r--r-- | configure.ac | 5 | ||||
| -rw-r--r-- | examples/c/reccalc/Makefile | 2 | ||||
| -rw-r--r-- | examples/c/reccalc/local.mk | 4 | ||||
| -rw-r--r-- | m4/flex.m4 | 16 |
4 files changed, 22 insertions, 5 deletions
diff --git a/configure.ac b/configure.ac index 68c54a12..c1b0c182 100644 --- a/configure.ac +++ b/configure.ac @@ -261,9 +261,8 @@ if ! "$LEX_IS_FLEX" || test "X$LEX" = X:; then AC_MSG_WARN([bypassing lex because flex is required]) LEX=: fi -AM_CONDITIONAL([FLEX_WORKS], [$LEX_IS_FLEX]) -AM_CONDITIONAL([FLEX_CXX_WORKS], - [$LEX_IS_FLEX && test $bison_cv_cxx_works = yes]) +AM_CONDITIONAL([FLEX_WORKS], [$LEX_IS_FLEX && $FLEX_SUPPORTS_HEADER_OPT]) +AM_CONDITIONAL([FLEX_CXX_WORKS], [$LEX_WORKS && test $bison_cv_cxx_works = yes]) AC_PROG_YACC AC_PROG_RANLIB AC_PROG_GNU_M4 diff --git a/examples/c/reccalc/Makefile b/examples/c/reccalc/Makefile index 84fbd3ee..a64ceedb 100644 --- a/examples/c/reccalc/Makefile +++ b/examples/c/reccalc/Makefile @@ -12,7 +12,7 @@ all: $(BASE) $(BISON) $(BISONFLAGS) --defines --xml --graph=$*.gv -o $*.c $< %.c %.h: %.l - $(FLEX) $(FLEXFLAGS) -o$*.c --header-file=$*.h $< + $(FLEX) $(FLEXFLAGS) -o$*.c --header=$*.h $< scan.o: parse.h parse.o: scan.h diff --git a/examples/c/reccalc/local.mk b/examples/c/reccalc/local.mk index de889789..0538f120 100644 --- a/examples/c/reccalc/local.mk +++ b/examples/c/reccalc/local.mk @@ -69,7 +69,9 @@ DASH = - $(AM_V_LEX)rm -f $@ $@.tmp $(AM_V_at)$(MKDIR_P) %D% $(AM_V_at)touch $@.tmp - $(AM_V_at)$(LEX) $(AM_LFLAGS) $(LFLAGS) -o%D%/scan.c --header-file=%D%/scan.h $(srcdir)/%D%/scan.l +## --header introduced in 2.5.6, renamed as --header-file in 2.6.4. +## Backward compatibility ensured since --header is an unambiguous prefix. + $(AM_V_at)$(LEX) $(AM_LFLAGS) $(LFLAGS) -o%D%/scan.c --header=%D%/scan.h $(srcdir)/%D%/scan.l $(AM_V_at)mv $@.tmp $@ @@ -41,6 +41,22 @@ else fi ]) + +AC_CACHE_CHECK([whether flex supports --header=FILE], + [ac_cv_prog_lex_supports_header_opt], +[if _AC_DO_VAR([LEX --header=conftest.h conftest.l]); then + ac_cv_prog_lex_supports_header_opt=yes +else + ac_cv_prog_lex_supports_header_opt=no +fi +]) +if test "$ac_cv_prog_lex_supports_header_opt" = yes; then + FLEX_SUPPORTS_HEADER_OPT=true +else + FLEX_SUPPORTS_HEADER_OPT=false +fi + + cat >conftest.l <<_ACEOF[ %% a { ECHO; } |