Advertise a minimum alignment for SharedMemory::Map().

base/shared_memory.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_SHARED_MEMORY_H_
 #define BASE_SHARED_MEMORY_H_
 
 #include "build/build_config.h"
 
 #include <string>
@@ skipping 124 matching lines @@
   // Not all platforms require this call.
   bool Delete(const std::string& name);
 
   // Opens a shared memory segment based on a name.
   // If read_only is true, opens for read-only access.
   // Returns true on success, false on failure.
   bool Open(const std::string& name, bool read_only);
 
   // Maps the shared memory into the caller's address space.
   // Returns true on success, false otherwise.  The memory address
-  // is accessed via the memory() accessor.
+  // is accessed via the memory() accessor.  The mapped address is guaranteed to
+  // have an alignment of at least kMapMinimumAlignment.
   bool Map(uint32 bytes);
+  enum { kMapMinimumAlignment = 32 };

[jar (doing other things), 2012/08/17 21:32:32]

nit: use MACRO_STYLE MAP_MINIMUM_ALIGNMENT  (this is a Chromium style issue).

[DaleCurtis, 2012/08/17 21:43:46]

Done.

 
   // Unmaps the shared memory from the caller's address space.
   // Returns true if successful; returns false on error or if the
   // memory is not mapped.
   bool Unmap();
 
   // Get the size of the shared memory backing file.
   // Note:  This size is only available to the creator of the
   // shared memory, and not to those that opened shared memory
   // created externally.
@@ skipping 107 matching lines @@
   }
 
  private:
   SharedMemory* shared_memory_;
   DISALLOW_COPY_AND_ASSIGN(SharedMemoryAutoLock);
 };
 
 }  // namespace base
 
 #endif  // BASE_SHARED_MEMORY_H_