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144 lines
3.8 KiB
C
144 lines
3.8 KiB
C
///////////////////////////////////////////////////////////////////////////////
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//
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/// \file physmem.h
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/// \brief Get the amount of physical memory
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//
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// Author: Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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#ifndef PHYSMEM_H
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#define PHYSMEM_H
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// Test for Windows first, because we want to use Windows-specific code
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// on Cygwin, which also has memory information available via sysconf(), but
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// on Cygwin 1.5 and older it gives wrong results (from our point of view).
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#if defined(_WIN32) || defined(__CYGWIN__)
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# ifndef _WIN32_WINNT
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# define _WIN32_WINNT 0x0500
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# endif
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# include <windows.h>
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#elif defined(__OS2__)
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# define INCL_DOSMISC
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# include <os2.h>
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#elif defined(__DJGPP__)
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# include <dpmi.h>
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#elif defined(HAVE_PHYSMEM_SYSCONF)
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# include <unistd.h>
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#elif defined(HAVE_PHYSMEM_SYSCTL)
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# ifdef HAVE_SYS_PARAM_H
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# include <sys/param.h>
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# endif
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# ifdef HAVE_SYS_SYSCTL_H
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# include <sys/sysctl.h>
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# endif
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#elif defined(HAVE_PHYSMEM_SYSINFO)
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# include <sys/sysinfo.h>
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#endif
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/// \brief Get the amount of physical memory in bytes
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///
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/// \return Amount of physical memory in bytes. On error, zero is
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/// returned.
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static inline uint64_t
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physmem(void)
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{
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uint64_t ret = 0;
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#if defined(_WIN32) || defined(__CYGWIN__)
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if ((GetVersion() & 0xFF) >= 5) {
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// Windows 2000 and later have GlobalMemoryStatusEx() which
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// supports reporting values greater than 4 GiB. To keep the
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// code working also on older Windows versions, use
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// GlobalMemoryStatusEx() conditionally.
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HMODULE kernel32 = GetModuleHandle("kernel32.dll");
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if (kernel32 != NULL) {
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BOOL (WINAPI *gmse)(LPMEMORYSTATUSEX) = GetProcAddress(
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kernel32, "GlobalMemoryStatusEx");
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if (gmse != NULL) {
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MEMORYSTATUSEX meminfo;
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meminfo.dwLength = sizeof(meminfo);
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if (gmse(&meminfo))
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ret = meminfo.ullTotalPhys;
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}
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}
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}
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if (ret == 0) {
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// GlobalMemoryStatus() is supported by Windows 95 and later,
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// so it is fine to link against it unconditionally. Note that
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// GlobalMemoryStatus() has no return value.
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MEMORYSTATUS meminfo;
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meminfo.dwLength = sizeof(meminfo);
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GlobalMemoryStatus(&meminfo);
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ret = meminfo.dwTotalPhys;
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}
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#elif defined(__OS2__)
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unsigned long mem;
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if (DosQuerySysInfo(QSV_TOTPHYSMEM, QSV_TOTPHYSMEM,
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&mem, sizeof(mem)) == 0)
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ret = mem;
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#elif defined(__DJGPP__)
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__dpmi_free_mem_info meminfo;
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if (__dpmi_get_free_memory_information(&meminfo) == 0
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&& meminfo.total_number_of_physical_pages
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!= (unsigned long)(-1))
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ret = (uint64_t)(meminfo.total_number_of_physical_pages)
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* 4096;
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#elif defined(HAVE_PHYSMEM_SYSCONF)
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const long pagesize = sysconf(_SC_PAGESIZE);
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const long pages = sysconf(_SC_PHYS_PAGES);
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if (pagesize != -1 || pages != -1)
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// According to docs, pagesize * pages can overflow.
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// Simple case is 32-bit box with 4 GiB or more RAM,
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// which may report exactly 4 GiB of RAM, and "long"
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// being 32-bit will overflow. Casting to uint64_t
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// hopefully avoids overflows in the near future.
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ret = (uint64_t)(pagesize) * (uint64_t)(pages);
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#elif defined(HAVE_PHYSMEM_SYSCTL)
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int name[2] = {
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CTL_HW,
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#ifdef HW_PHYSMEM64
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HW_PHYSMEM64
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#else
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HW_PHYSMEM
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#endif
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};
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union {
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uint32_t u32;
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uint64_t u64;
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} mem;
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size_t mem_ptr_size = sizeof(mem.u64);
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if (sysctl(name, 2, &mem.u64, &mem_ptr_size, NULL, 0) != -1) {
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// IIRC, 64-bit "return value" is possible on some 64-bit
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// BSD systems even with HW_PHYSMEM (instead of HW_PHYSMEM64),
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// so support both.
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if (mem_ptr_size == sizeof(mem.u64))
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ret = mem.u64;
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else if (mem_ptr_size == sizeof(mem.u32))
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ret = mem.u32;
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}
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#elif defined(HAVE_PHYSMEM_SYSINFO)
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struct sysinfo si;
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if (sysinfo(&si) == 0)
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ret = (uint64_t)(si.totalram) * si.mem_unit;
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#endif
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return ret;
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}
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#endif
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