Introduced alignof support like the one for check_sizeof

1 files changed, 79 insertions, 0 deletions

diff --git a/xmake/modules/lib/detect/check_alignof.lua b/xmake/modules/lib/detect/check_alignof.lua
new file mode 100644
index 000000000..d8b1561f4
--- /dev/null
+++ b/xmake/modules/lib/detect/check_alignof.lua
@@ -0,0 +1,79 @@
+--!A cross-platform build utility based on Lua
+--
+-- Licensed 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 (C) 2026-present, Xmake Open Source Community.
+--
+-- @author      karurochari
+-- @file        check_alignof.lua
+--
+
+-- imports
+import("lib.detect.check_cxxsnippets")
+
+local binary_match_pattern = 'INFO:align%[(%d+)%]'
+
+local check_alignof_template = [[
+#define ALIGN (alignof(${TYPE}))
+static char info_align[] =  {'I', 'N', 'F', 'O', ':', 'a','l','i','g','n','[',
+  ('0' + ((ALIGN / 10000)%10)),
+  ('0' + ((ALIGN / 1000)%10)),
+  ('0' + ((ALIGN / 100)%10)),
+  ('0' + ((ALIGN / 10)%10)),
+  ('0' +  (ALIGN    % 10)),
+  ']',
+  '\0'};
+
+int main(int argc, char *argv[]) {
+  int require = 0;
+  require += info_align[argc];
+  (void)argv;
+  return require;
+}]]
+
+function _binary_match(content)
+    local match = content:match(binary_match_pattern)
+    if match then
+        return match:ltrim("0")
+    end
+end
+
+-- check the alignment of type
+--
+-- @param typename  the typename
+-- @param opt       the argument options
+--                  e.g.
+--                  { verbose = false, target = [target|option], includes = "stdio.h"
+--                  , configs = {defines = "xx", cxflags = ""}}
+--
+-- @return          the type alignment
+--
+-- @code
+-- local align = check_alignof("long")
+-- local align = check_alignof("std::string", {includes = "string"})
+-- @endcode
+--
+-- check the alignment of a C/C++ type
+--
+-- @param typename   the type name, e.g. "int", "size_t"
+-- @param opt        the options, e.g. {includes = {"stddef.h"}, target = target}
+-- @return           the type alignment in bytes, or -1
+--
+function main(typename, opt)
+    local snippets = check_alignof_template:gsub('${TYPE}', typename)
+    local ok, size = check_cxxsnippets(snippets, table.join(table.wrap(opt), {binary_match = _binary_match}))
+    if ok then
+        return size
+    end
+end
+