llvm-mirror/lib/System/Win32/Process.cpp

//===- Win32/Process.cpp - Win32 Process Implementation ------- -*- C++ -*-===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Jeff Cohen and is distributed under the 
// University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file provides the Win32 specific implementation of the Process class.
//
//===----------------------------------------------------------------------===//

#include "Win32.h"

//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only Win32 specific code 
//===          and must not be UNIX code
//===----------------------------------------------------------------------===//

namespace llvm {
using namespace sys;

// This function retrieves the page size using GetSystemInfo and is present
// solely so it can be called once in Process::GetPageSize to initialize the
// static variable PageSize.
inline unsigned GetPageSizeOnce() {
  // NOTE: A 32-bit application running under WOW64 is supposed to use
  // GetNativeSystemInfo.  However, this interface is not present prior
  // to Windows XP so to use it requires dynamic linking.  It is not clear
  // how this affects the reported page size, if at all.  One could argue
  // that LLVM ought to run as 64-bits on a 64-bit system, anyway.
  SYSTEM_INFO info;
  GetSystemInfo(&info);
  return static_cast<unsigned>(info.dwPageSize);
}

unsigned 
Process::GetPageSize() {
  static const unsigned PageSize = GetPageSizeOnce();
  return PageSize;
}

}
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