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Annotation of embedaddon/libiconv/srcm4/warn-on-use.m4, revision 1.1

1.1     ! misho       1: # warn-on-use.m4 serial 4
        !             2: dnl Copyright (C) 2010-2011 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: # 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: # If you assume C89, then it is generally safe to assume declarations
        !            22: # for functions declared in that standard (such as gets) without
        !            23: # needing gl_WARN_ON_USE_PREPARE.
        !            24: AC_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
        !            30: dnl FIXME: gl_Symbol must be used unquoted until we can assume
        !            31: dnl 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: ])