Create a "GetWOW64Status()" utility function and make the rest of the codebas...

base/win/windows_version.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/win/windows_version.h"
 
 #include <windows.h>
 
 #include "base/logging.h"
 
 namespace base {
@@ skipping 49 matching lines @@
     GetVersionEx(reinterpret_cast<OSVERSIONINFOW*>(&version_info));
     service_pack_major = version_info.wServicePackMajor;
     service_pack_minor = version_info.wServicePackMinor;
     checked_version = true;
   }
 
   *major = service_pack_major;
   *minor = service_pack_minor;
 }
 
+WOW64Status GetWOW64Status() {
+  static WOW64Status wow64_status =
+      GetWOW64StatusForProcess(GetCurrentProcess());
+  return wow64_status;
+}
+
+WOW64Status GetWOW64StatusForProcess(HANDLE process_handle) {
+  typedef BOOL (WINAPI* IsWow64ProcessFunc)(HANDLE, PBOOL);
+  IsWow64ProcessFunc is_wow64_process = reinterpret_cast<IsWow64ProcessFunc>(
+      GetProcAddress(GetModuleHandle(L"kernel32.dll"), "IsWow64Process"));

[rvargas (doing something else), 2011/03/04 00:12:18]

Can we save this pointer? GetProcAddress is not that fast, and this may be
called a bunch of times for each process that we want to launch.

[Peter Kasting, 2011/03/04 01:11:48]

But the entire return value is cached in GetWOW64Status().  So this should only
be called once.

[rvargas (doing something else), 2011/03/04 01:21:49]

Even better :)

+  if (!is_wow64_process)
+    return WOW64_DISABLED;
+  BOOL is_wow64 = FALSE;
+  if (!(*is_wow64_process)(process_handle, &is_wow64))
+    return WOW64_UNKNOWN;
+  return is_wow64 ? WOW64_ENABLED : WOW64_DISABLED;
+}
+
 }  // namespace win
 }  // namespace base