# warn-on-use.m4 serial 6

dnl Copyright (C) 2010-2020 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)

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

# If the module 'posixcheck' is in use:

#

# 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.

#

# It is generally safe to assume declarations for functions declared

# in the intersection of C89 and C11 (such as printf) without

# needing gl_WARN_ON_USE_PREPARE.

AC_DEFUN([gl_WARN_ON_USE_PREPARE],

[

  m4_ifdef([gl_POSIXCHECK],

    [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

dnl FIXME: gl_Symbol must be used unquoted until we can assume

dnl autoconf 2.64 or newer.

     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

    ])

])