1 ///////////////////////////////////////////////////////////////////////////////
4 /// \brief Get the amount of physical memory
6 // This code has been put into the public domain.
8 // This library is distributed in the hope that it will be useful,
9 // but WITHOUT ANY WARRANTY; without even the implied warranty of
10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
12 ///////////////////////////////////////////////////////////////////////////////
17 #if defined(HAVE_PHYSMEM_SYSCTL) || defined(HAVE_NCPU_SYSCTL)
18 # ifdef HAVE_SYS_PARAM_H
19 # include <sys/param.h>
21 # ifdef HAVE_SYS_SYSCTL_H
22 # include <sys/sysctl.h>
26 #if defined(HAVE_PHYSMEM_SYSCONF) || defined(HAVE_NCPU_SYSCONF)
32 # define _WIN32_WINNT 0x0500
38 /// \brief Get the amount of physical memory in bytes
40 /// \return Amount of physical memory in bytes. On error, zero is
42 static inline uint64_t
47 #if defined(HAVE_PHYSMEM_SYSCONF)
48 const long pagesize = sysconf(_SC_PAGESIZE);
49 const long pages = sysconf(_SC_PHYS_PAGES);
50 if (pagesize != -1 || pages != -1)
51 // According to docs, pagesize * pages can overflow.
52 // Simple case is 32-bit box with 4 GiB or more RAM,
53 // which may report exactly 4 GiB of RAM, and "long"
54 // being 32-bit will overflow. Casting to uint64_t
55 // hopefully avoids overflows in the near future.
56 ret = (uint64_t)(pagesize) * (uint64_t)(pages);
58 #elif defined(HAVE_PHYSMEM_SYSCTL)
59 int name[2] = { CTL_HW, HW_PHYSMEM };
61 size_t mem_ptr_size = sizeof(mem);
62 if (!sysctl(name, 2, &mem, &mem_ptr_size, NULL, NULL)) {
63 // Some systems use unsigned int as the "return value".
64 // This makes a difference on 64-bit boxes.
65 if (mem_ptr_size != sizeof(mem)) {
66 if (mem_ptr_size == sizeof(unsigned int))
67 ret = *(unsigned int *)(&mem);
74 MEMORYSTATUSEX meminfo;
75 meminfo.dwLength = sizeof(meminfo);
76 if (GlobalMemoryStatusEx(&meminfo))
77 ret = meminfo.ullTotalPhys;