Function totalSystemMemory [src]
Returns the total system memory, in bytes as a u64.
We return a u64 instead of usize due to PAE on ARM
and Linux's /proc/meminfo reporting more memory when
using QEMU user mode emulation.
Prototype
pub fn totalSystemMemory() TotalSystemMemoryError!u64
Possible Errors
Source
pub fn totalSystemMemory() TotalSystemMemoryError!u64 {
switch (native_os) {
.linux => {
var info: std.os.linux.Sysinfo = undefined;
const result: usize = std.os.linux.sysinfo(&info);
if (std.os.linux.E.init(result) != .SUCCESS) {
return error.UnknownTotalSystemMemory;
}
// Promote to u64 to avoid overflow on systems where info.totalram is a 32-bit usize
return @as(u64, info.totalram) * info.mem_unit;
},
.freebsd => {
var physmem: c_ulong = undefined;
var len: usize = @sizeOf(c_ulong);
posix.sysctlbynameZ("hw.physmem", &physmem, &len, null, 0) catch |err| switch (err) {
error.UnknownName => unreachable,
else => return error.UnknownTotalSystemMemory,
};
return @as(u64, @intCast(physmem));
},
// whole Darwin family
.driverkit, .ios, .macos, .tvos, .visionos, .watchos => {
// "hw.memsize" returns uint64_t
var physmem: u64 = undefined;
var len: usize = @sizeOf(u64);
posix.sysctlbynameZ("hw.memsize", &physmem, &len, null, 0) catch |err| switch (err) {
error.PermissionDenied => unreachable, // only when setting values,
error.SystemResources => unreachable, // memory already on the stack
error.UnknownName => unreachable, // constant, known good value
else => return error.UnknownTotalSystemMemory,
};
return physmem;
},
.openbsd => {
const mib: [2]c_int = [_]c_int{
posix.CTL.HW,
posix.HW.PHYSMEM64,
};
var physmem: i64 = undefined;
var len: usize = @sizeOf(@TypeOf(physmem));
posix.sysctl(&mib, &physmem, &len, null, 0) catch |err| switch (err) {
error.NameTooLong => unreachable, // constant, known good value
error.PermissionDenied => unreachable, // only when setting values,
error.SystemResources => unreachable, // memory already on the stack
error.UnknownName => unreachable, // constant, known good value
else => return error.UnknownTotalSystemMemory,
};
assert(physmem >= 0);
return @as(u64, @bitCast(physmem));
},
.windows => {
var sbi: windows.SYSTEM_BASIC_INFORMATION = undefined;
const rc = windows.ntdll.NtQuerySystemInformation(
.SystemBasicInformation,
&sbi,
@sizeOf(windows.SYSTEM_BASIC_INFORMATION),
null,
);
if (rc != .SUCCESS) {
return error.UnknownTotalSystemMemory;
}
return @as(u64, sbi.NumberOfPhysicalPages) * sbi.PageSize;
},
else => return error.UnknownTotalSystemMemory,
}
}