1# warn-on-use.m4 serial 5
2dnl Copyright (C) 2010-2015 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7# gl_WARN_ON_USE_PREPARE(INCLUDES, NAMES)
8# ---------------------------------------
9# For each whitespace-separated element in the list of NAMES, define
10# HAVE_RAW_DECL_name if the function has a declaration among INCLUDES
11# even after being undefined as a macro.
12#
13# See warn-on-use.h for some hints on how to poison function names, as
14# well as ideas on poisoning global variables and macros.  NAMES may
15# include global variables, but remember that only functions work with
16# _GL_WARN_ON_USE.  Typically, INCLUDES only needs to list a single
17# header, but if the replacement header pulls in other headers because
18# some systems declare functions in the wrong header, then INCLUDES
19# should do likewise.
20#
21# It is generally safe to assume declarations for functions declared
22# in the intersection of C89 and C11 (such as printf) without
23# needing gl_WARN_ON_USE_PREPARE.
24AC_DEFUN([gl_WARN_ON_USE_PREPARE],
25[
26  m4_foreach_w([gl_decl], [$2],
27    [AH_TEMPLATE([HAVE_RAW_DECL_]AS_TR_CPP(m4_defn([gl_decl])),
28      [Define to 1 if ]m4_defn([gl_decl])[ is declared even after
29       undefining macros.])])dnl
30dnl FIXME: gl_Symbol must be used unquoted until we can assume
31dnl autoconf 2.64 or newer.
32  for gl_func in m4_flatten([$2]); do
33    AS_VAR_PUSHDEF([gl_Symbol], [gl_cv_have_raw_decl_$gl_func])dnl
34    AC_CACHE_CHECK([whether $gl_func is declared without a macro],
35      gl_Symbol,
36      [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$1],
37[@%:@undef $gl_func
38  (void) $gl_func;])],
39        [AS_VAR_SET(gl_Symbol, [yes])], [AS_VAR_SET(gl_Symbol, [no])])])
40    AS_VAR_IF(gl_Symbol, [yes],
41      [AC_DEFINE_UNQUOTED(AS_TR_CPP([HAVE_RAW_DECL_$gl_func]), [1])
42       dnl shortcut - if the raw declaration exists, then set a cache
43       dnl variable to allow skipping any later AC_CHECK_DECL efforts
44       eval ac_cv_have_decl_$gl_func=yes])
45    AS_VAR_POPDEF([gl_Symbol])dnl
46  done
47])
48