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# warn-on-use.m4 serial 2

dnl Copyright (C) 2010 Free Software Foundation, Inc.

dnl This file is free software; the Free Software Foundation

dnl gives unlimited permission to copy and/or distribute it,

dnl with or without modifications, as long as this notice is preserved.

# gl_WARN_ON_USE_PREPARE(INCLUDES, NAMES)

# ---------------------------------------

# For each whitespace-separated element in the list of NAMES, define

# HAVE_RAW_DECL_name if the function has a declaration among INCLUDES

# even after being undefined as a macro.

#

# See warn-on-use.h for some hints on how to poison function names, as

# well as ideas on poisoning global variables and macros.  NAMES may

# include global variables, but remember that only functions work with

# _GL_WARN_ON_USE.  Typically, INCLUDES only needs to list a single

# header, but if the replacement header pulls in other headers because

# some systems declare functions in the wrong header, then INCLUDES

# should do likewise.

#

# If you assume C89, then it is generally safe to assume declarations

# for functions declared in that standard (such as gets) without

# needing gl_WARN_ON_USE_PREPARE.

AC_DEFUN([gl_WARN_ON_USE_PREPARE],

[

  m4_foreach_w([gl_decl], [$2],

    [AH_TEMPLATE([HAVE_RAW_DECL_]AS_TR_CPP(m4_defn([gl_decl])),

      [Define to 1 if ]m4_defn([gl_decl])[ is declared even after

       undefining macros.])])dnl

  for gl_func in m4_flatten([$2]); do

    AS_VAR_PUSHDEF([gl_Symbol], [gl_cv_have_raw_decl_$gl_func])dnl

    AC_CACHE_CHECK([whether $gl_func is declared without a macro],

      gl_Symbol,

      [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$1],

[@%:@undef $gl_func

  (void) $gl_func;])],

        [AS_VAR_SET(gl_Symbol, [yes])], [AS_VAR_SET(gl_Symbol, [no])])])

     AS_VAR_IF(gl_Symbol, [yes],

       [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_RAW_DECL_$gl_func]), [1])

       dnl shortcut - if the raw declaration exists, then set a cache

       dnl variable to allow skipping any later AC_CHECK_DECL efforts

       eval ac_cv_have_decl_$gl_func=yes])

    AS_VAR_POPDEF([gl_Symbol])dnl

  done

])