| # |
| # Licensed to the Apache Software Foundation (ASF) under one or more |
| # contributor license agreements. See the NOTICE file distributed |
| # with this work for additional information regarding copyright |
| # ownership. The ASF licenses this file to you under the Apache |
| # License, Version 2.0 (the License); you may not use this file |
| # except in compliance with the License. You may obtain a copy of |
| # the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |
| # implied. See the License for the specific language governing |
| # permissions and limitations under the License. |
| # |
| # Copyright 1999-2008 Rogue Wave Software, Inc. |
| # |
| |
| # AC_C89_OFFSETOF(ACTION-IF-TRUE, ACTION-IF-FALSE) |
| # ---------------------------------------------- |
| # Perform ACTION-IF-TRUE if standard headers define offsetof() macro. |
| # Otherwise, performs ACTION-IF-FALSE. |
| # |
| # TODO: Define offsetof() if not found as follows: |
| # offsetof(T, m) (((const char*)&((T*)0)->m) - ((const char*)(T*)0)) |
| AC_DEFUN([AC_C89_OFFSETOF], |
| [ |
| AS_VAR_PUSHDEF([ac_Var], [ac_cv_c_offsetof]) |
| AC_CACHE_CHECK([for offsetof], [ac_Var], |
| [AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT |
| struct S { int i[[2]][[2]]; };], |
| [return !(offsetof (struct S, i [[0]][[1]]) |
| != offsetof (struct S, i [[1]][[0]]));])], |
| [AS_VAR_SET([ac_Var], [yes])], |
| [AS_VAR_SET([ac_Var], [no])])]) |
| AS_IF([test AS_VAR_GET([ac_Var]) = yes], [$1], [$2]) |
| AS_VAR_POPDEF([ac_Var]) |
| ])# AC_C89_OFFSETOF |
| |
