kc3-lang/automake/tests/lex-noyywrap.test

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• Hash : eb147a19
  Author :
  Date : 2011-05-25T19:05:15
  

  lex tests: avoid spurious failures when LEXLIB isn't found
  
  The AC_PROG_LEX Autoconf macro does not diagnose a failure to find
  the "lex library" expected to provide a `yywrap' function (function
  which is required to link most lex-generated programs).  On the
  contrary, when all the link attempts (i.e., with `-ll' and `-lfl')
  fail, configure declares that no lex library is needed, and simply
  proceeds with the configuration process -- only for the build to
  possibly fail later, at make time.
  
  This behaviour might be (partly) intended; the Autoconf manual
  reads:
   ``You are encouraged to use Flex in your sources, since it is
     both more pleasant to use than plain Lex and the C source
     it produces is portable.  In order to ensure portability,
     however, you must either provide a function `yywrap' or, if
     you don't use it (e.g., your scanner has no `#include'-like
     feature), simply include a `%noyywrap' statement in the
     scanner's source.''
  
  This AC_PROG_LEX behaviour is causing some spurious failures of the
  Automake testsuite in environments which lack a proper library
  providing `yywrap' (this happens for example in	Linux->MinGW cross
  compilations).  But at this point is clear that a proper workaround
  is to simply provide a fall-back implementation of `yywrap' in our
  lexers.
  
  * tests/cond35.test: Provide a dummy `yywrap' function.
  * tests/lex3.test: Likewise.
  * tests/lexvpath.test: Likewise.
  * tests/silent-many-gcc.test: Likewise.
  * tests/silent-many-generic.test: Likewise.
  * tests/silent-lex-gcc.test: Likewise, and a dummy `main' too.
  * tests/silent-lex-generic.test: Likewise.
  * tests/lex-lib.test: New test.
  * tests/lex-libobj.test: New test.
  * tests/lex-nowrap.test: New test.
  * tests/Makefile.am (TESTS): Update.
  * THANKS: Update.
  
  Thanks to Russ Allbery for the suggestion.
  

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• tests/lex-noyywrap.test

• #! /bin/sh
  # Copyright (C) 1999, 2001, 2002, 2003, 2004, 2010, 2011 Free Software
  # Foundation, Inc.
  #
  # This program is free software; you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation; either version 2, or (at your option)
  # any later version.
  #
  # This program is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  
  # Check Lex support with flex using the `%noyywrap' option.
  
  required='cc flex'
  . ./defs || Exit 1
  
  cat >> configure.in << 'END'
  AC_PROG_CC
  AM_PROG_LEX
  AC_OUTPUT
  END
  
  cat > Makefile.am << 'END'
  bin_PROGRAMS = foo
  foo_SOURCES = foo.l
  
  .PHONY: test-no-lexlib
  check-local: test-no-lexlib
  test-no-lexlib:
  	test x'$(LEXLIB)' = x'none needed'
  END
  
  cat > foo.l << 'END'
  %option noyywrap
  %%
  "GOOD"   return EOF;
  .
  %%
  int main (void)
  {
    /* We don't use a 'while' loop here (like a real lexer would do)
       to avoid possible hangs. */
    if (yylex () == EOF)
      return 0;
    else
      return 1;
  }
  END
  
  $ACLOCAL
  $AUTOCONF
  $AUTOMAKE -a
  
  ./configure LEXLIB="none needed"
  
  # Program should build and run.
  $MAKE
  if cross_compiling; then :; else
    echo GOOD | ./foo
    echo BAD | ./foo && Exit 1
  fi
  
  # Sanity check on distribution.
  $MAKE distcheck DISTCHECK_CONFIGURE_FLAGS='LEXLIB="none needed"'
  
  :
  

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