Macro: ac_check_cc_opt

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Synopsis

  `AC_CHECK_CC_OPT(flag, cachevarname)`

Version

  1.1.1.1 (2001/07/26) guidod @ ac-archive-0.5.39

Author

Description

  AC_CHECK_CC_OPT(-fvomit-frame,vomitframe) would show a message as like "checking wether gcc accepts -fvomit-frame ... no" and sets the shell-variable $vomitframe to either "-fvomit-frame" or (in this case) just a simple "". In many cases you would then call AC_SUBST(_fvomit_frame_,$vomitframe) to create a substitution that could be fed as "CFLAGS = @_funsigned_char_@ @_fvomit_frame_@

  in consequence this function is much more general than their specific counterparts like ac_cxx_rtti.m4 that will test for -fno-rtti -fno-exceptions

M4 Source Code

      dml @author  Guido Draheim <guidod@gmx.de>

      AC_DEFUN(AC_CHECK_CC_OPT,
      [AC_CACHE_CHECK(whether ${CC-cc} accepts [$1], [$2],
      [AC_SUBST($2)
      echo 'void f(){}' > conftest.c
      if test -z "`${CC-cc} -c $1 conftest.c 2>&1`"; then
        $2="$1"
      else
        $2=""
      fi
      rm -f conftest*
      ])])