2 * Copyright (C) 2012 Apple Inc. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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29 #include "StdLibExtras.h"
31 #include <sys/param.h>
32 #include <sys/types.h>
33 #include <sys/sysctl.h>
44 static const size_t ramSizeGuess = 128 * MB;
46 static size_t computeRAMSize()
55 length = sizeof(int64_t);
56 int sysctlResult = sysctl(mib, 2, &ramSize, &length, 0, 0);
57 if (sysctlResult == -1)
59 return ramSize > std::numeric_limits<size_t>::max() ? std::numeric_limits<size_t>::max() : static_cast<size_t>(ramSize);
61 long pages = sysconf(_SC_PHYS_PAGES);
62 long pageSize = sysconf(_SC_PAGE_SIZE);
63 if (pages == -1 || pageSize == -1)
65 return pages * pageSize;
68 status.dwLength = sizeof(status);
69 GlobalMemoryStatus(&status);
70 if (status.dwTotalPhys <= 0)
72 return status.dwTotalPhys;
74 MEMORYSTATUSEX status;
75 status.dwLength = sizeof(status);
76 bool result = GlobalMemoryStatusEx(&status);
79 return status.ullTotalPhys;
82 if (stat("/proc", &mst))
90 static const size_t ramSize = computeRAMSize();