m4/warnings.m4

   1 # warnings.m4 serial 11
   2 dnl Copyright (C) 2008-2014 Free Software Foundation, Inc.
   3 dnl This file is free software; the Free Software Foundation
   4 dnl gives unlimited permission to copy and/or distribute it,
   5 dnl with or without modifications, as long as this notice is preserved.
   6
   7 dnl From Simon Josefsson
   8
   9 # gl_AS_VAR_APPEND(VAR, VALUE)
  10 # ----------------------------
  11 # Provide the functionality of AS_VAR_APPEND if Autoconf does not have it.
  12 m4_ifdef([AS_VAR_APPEND],
  13 [m4_copy([AS_VAR_APPEND], [gl_AS_VAR_APPEND])],
  14 [m4_define([gl_AS_VAR_APPEND],
  15 [AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])])
  16
  17
  18 # gl_COMPILER_OPTION_IF(OPTION, [IF-SUPPORTED], [IF-NOT-SUPPORTED],
  19 #                       [PROGRAM = AC_LANG_PROGRAM()])
  20 # -----------------------------------------------------------------
  21 # Check if the compiler supports OPTION when compiling PROGRAM.
  22 #
  23 # FIXME: gl_Warn must be used unquoted until we can assume Autoconf
  24 # 2.64 or newer.
  25 AC_DEFUN([gl_COMPILER_OPTION_IF],
  26 [AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_[]_AC_LANG_ABBREV[]_$1])dnl
  27 AS_VAR_PUSHDEF([gl_Flags], [_AC_LANG_PREFIX[]FLAGS])dnl
  28 AS_LITERAL_IF([$1],
  29   [m4_pushdef([gl_Positive], m4_bpatsubst([$1], [^-Wno-], [-W]))],
  30   [gl_positive="$1"
  31 case $gl_positive in
  32   -Wno-*) gl_positive=-W`expr "X$gl_positive" : 'X-Wno-\(.*\)'` ;;
  33 esac
  34 m4_pushdef([gl_Positive], [$gl_positive])])dnl
  35 AC_CACHE_CHECK([whether _AC_LANG compiler handles $1], m4_defn([gl_Warn]), [
  36   gl_save_compiler_FLAGS="$gl_Flags"
  37   gl_AS_VAR_APPEND(m4_defn([gl_Flags]),
  38     [" $gl_unknown_warnings_are_errors ]m4_defn([gl_Positive])["])
  39   AC_LINK_IFELSE([m4_default([$4], [AC_LANG_PROGRAM([])])],
  40                  [AS_VAR_SET(gl_Warn, [yes])],
  41                  [AS_VAR_SET(gl_Warn, [no])])
  42   gl_Flags="$gl_save_compiler_FLAGS"
  43 ])
  44 AS_VAR_IF(gl_Warn, [yes], [$2], [$3])
  45 m4_popdef([gl_Positive])dnl
  46 AS_VAR_POPDEF([gl_Flags])dnl
  47 AS_VAR_POPDEF([gl_Warn])dnl
  48 ])
  49
  50 # gl_UNKNOWN_WARNINGS_ARE_ERRORS
  51 # ------------------------------
  52 # Clang doesn't complain about unknown warning options unless one also
  53 # specifies -Wunknown-warning-option -Werror.  Detect this.
  54 AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS],
  55 [gl_COMPILER_OPTION_IF([-Werror -Wunknown-warning-option],
  56    [gl_unknown_warnings_are_errors='-Wunknown-warning-option -Werror'],
  57    [gl_unknown_warnings_are_errors=])])
  58
  59 # gl_WARN_ADD(OPTION, [VARIABLE = WARN_CFLAGS],
  60 #             [PROGRAM = AC_LANG_PROGRAM()])
  61 # ---------------------------------------------
  62 # Adds parameter to WARN_CFLAGS if the compiler supports it when
  63 # compiling PROGRAM.  For example, gl_WARN_ADD([-Wparentheses]).
  64 #
  65 # If VARIABLE is a variable name, AC_SUBST it.
  66 AC_DEFUN([gl_WARN_ADD],
  67 [AC_REQUIRE([gl_UNKNOWN_WARNINGS_ARE_ERRORS])
  68 gl_COMPILER_OPTION_IF([$1],
  69   [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]), [" $1"])],
  70   [],
  71   [$3])
  72 m4_ifval([$2],
  73          [AS_LITERAL_IF([$2], [AC_SUBST([$2])])],
  74          [AC_SUBST([WARN_CFLAGS])])dnl
  75 ])
  76
  77 # Local Variables:
  78 # mode: autoconf
  79 # End: