This is the continuation of the Getting System information in OSX and iOS using Delphi (XE2, XE3, XE4) Part 1 article.

Inside of the Posix.SysSysctl unit (which is the translation for the sysctl.h file) you can find a set of arrays (CTL_NAMES, CTL_KERN_NAMES, CTL_HW_NAMES, CTL_USER_NAMES, CTL_VM_NAMES) which contains the alias names for the system information elements, so using the items of these arrays you can build the name parameter for the SysCtlByName method.

For example if you want to access the kernel version you can build the alias like so

  Name:=PAnsiChar(CTL_NAMES[CTL_KERN].ctl_name+'.'+CTL_KERN_NAMES[KERN_VERSION].ctl_name);//kern.version

And then using the SysCtlByName method

function KernelVersion: AnsiString;
var
  res : Integer;
  len : size_t;
  p, Name: PAnsiChar;
begin
  len := SizeOf(Result);
  Name:=PAnsiChar(CTL_NAMES[CTL_KERN].ctl_name+'.'+CTL_KERN_NAMES[KERN_VERSION].ctl_name);
  res:=SysCtlByName(Name, nil, @len, nil, 0);
   if (len>0) and (res=0)  then
   begin
     GetMem(p, len);
     try
       res:=SysCtlByName(Name, p, @len, nil, 0);
       if res=0 then
        Result:=p;
     finally
       FreeMem(p);
     end;
   end;
end;

Another option is use these definitions for build a set of methods to retrieve all the system info included in these structs.

Try the next sample project.

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.Classes,
  System.Types,
  Posix.Errno,
  Posix.SysTypes,
  Posix.SysSysctl,
  System.SysUtils;

function GetsysctlIntValue(mib: TIntegerDynArray) : integer;
var
  len : size_t;
  res : integer;
begin
   len := sizeof(Result);
   res:=sysctl(@mib[0], 2, @Result, @len, nil, 0);
   if res<>0 then
    Result:=-1;// RaiseLastOSError;
end;

function GetsysctlInt64Value(mib: TIntegerDynArray) : Int64;
var
  len : size_t;
  res : integer;
begin
   len := sizeof(Result);
   res:=sysctl(@mib[0], 2, @Result, @len, nil, 0);
   if res<>0 then
     Result:=-1; //RaiseLastOSError;
end;

function GetsysctlStrValue(mib: TIntegerDynArray) : AnsiString;
var
  len : size_t;
  p   : PAnsiChar;
  res : integer;
begin
   Result:='';
   res:=sysctl(@mib[0], 2, nil, @len, nil, 0);
   if (len>0) and (res=0)  then
   begin
     GetMem(p, len);
     try
       res:=sysctl(@mib[0], 2, p, @len, nil, 0);
       if res=0 then
        Result:=p;
     finally
       FreeMem(p);
     end;
   end;
end;

procedure  ListKernelValues;
var
  mib : TIntegerDynArray;
  i   : Integer;
begin
 Writeln('High kernel limits');
 Writeln('------------------');
 for i:=0 to KERN_MAXID-1 do
 begin
    mib:=TIntegerDynArray.Create(CTL_KERN, i);
    case CTL_KERN_NAMES[i].ctl_type of
     CTLTYPE_NODE  :  Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_KERN].ctl_name, CTL_KERN_NAMES[i].ctl_name, '[node]']));
     CTLTYPE_OPAQUE:  Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_KERN].ctl_name, CTL_KERN_NAMES[i].ctl_name, '[structure]']));
     CTLTYPE_INT   :  Writeln(Format('%s.%-18s %d',[CTL_NAMES[CTL_KERN].ctl_name, CTL_KERN_NAMES[i].ctl_name, GetsysctlIntValue(mib)]));
     CTLTYPE_QUAD  :  Writeln(Format('%s.%-18s %d',[CTL_NAMES[CTL_KERN].ctl_name, CTL_KERN_NAMES[i].ctl_name, GetsysctlInt64Value(mib)]));
     CTLTYPE_STRING : Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_KERN].ctl_name, CTL_KERN_NAMES[i].ctl_name, GetsysctlStrValue(mib)]));
    end;
 end;
 Writeln;
end;

procedure  ListGenericCPU_IO_Values;
var
  mib : TIntegerDynArray;
  i   : Integer;
begin
 Writeln('Generic CPU, I/O');
 Writeln('-----------------');
 for i:=0 to HW_MAXID-1 do
 begin
    mib:=TIntegerDynArray.Create(CTL_HW, i);
    case CTL_HW_NAMES[i].ctl_type of
     CTLTYPE_NODE  :  Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_HW].ctl_name, CTL_HW_NAMES[i].ctl_name, '[node]']));
     CTLTYPE_OPAQUE:  Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_HW].ctl_name, CTL_HW_NAMES[i].ctl_name, '[structure]']));
     CTLTYPE_INT   :  Writeln(Format('%s.%-18s %d',[CTL_NAMES[CTL_HW].ctl_name, CTL_HW_NAMES[i].ctl_name, GetsysctlIntValue(mib)]));
     CTLTYPE_QUAD  :  Writeln(Format('%s.%-18s %d',[CTL_NAMES[CTL_HW].ctl_name, CTL_HW_NAMES[i].ctl_name, GetsysctlInt64Value(mib)]));
     CTLTYPE_STRING : Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_HW].ctl_name, CTL_HW_NAMES[i].ctl_name, GetsysctlStrValue(mib)]));
    end;
 end;
 Writeln;
end;

procedure  ListUserLevelValues;
var
  mib : TIntegerDynArray;
  i   : Integer;
begin
 mib:=TIntegerDynArray.Create(CTL_USER, 0);
 Writeln('User-level');
 Writeln('----------');
 for i:=0 to USER_MAXID-1 do
 begin
    mib[1]:=i;
    case CTL_USER_NAMES[i].ctl_type of
     CTLTYPE_NODE  :  Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_USER].ctl_name, CTL_USER_NAMES[i].ctl_name, '[node]']));
     CTLTYPE_OPAQUE:  Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_USER].ctl_name, CTL_USER_NAMES[i].ctl_name, '[structure]']));
     CTLTYPE_INT   :  Writeln(Format('%s.%-18s %d',[CTL_NAMES[CTL_USER].ctl_name, CTL_USER_NAMES[i].ctl_name, GetsysctlIntValue(mib)]));
     CTLTYPE_QUAD  :  Writeln(Format('%s.%-18s %d',[CTL_NAMES[CTL_USER].ctl_name, CTL_USER_NAMES[i].ctl_name, GetsysctlInt64Value(mib)]));
     CTLTYPE_STRING : Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_USER].ctl_name, CTL_USER_NAMES[i].ctl_name, GetsysctlStrValue(mib)]));
    end;
 end;
 Writeln;
end;

procedure  ListVMValues;
var
  mib : TIntegerDynArray;
  i   : Integer;
begin
 Writeln('Virtual memory');
 Writeln('-------------');
 for i:=0 to VM_MAXID-1 do
 begin
    mib:=TIntegerDynArray.Create(CTL_VM, i);
    case CTL_VM_NAMES[i].ctl_type of
     CTLTYPE_NODE  :  Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_VM].ctl_name, CTL_VM_NAMES[i].ctl_name, '[node]']));
     CTLTYPE_OPAQUE:  Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_VM].ctl_name, CTL_VM_NAMES[i].ctl_name, '[structure]']));
     CTLTYPE_INT   :  Writeln(Format('%s.%-18s %d',[CTL_NAMES[CTL_VM].ctl_name, CTL_VM_NAMES[i].ctl_name, GetsysctlIntValue(mib)]));
     CTLTYPE_QUAD  :  Writeln(Format('%s.%-18s %d',[CTL_NAMES[CTL_VM].ctl_name, CTL_VM_NAMES[i].ctl_name, GetsysctlInt64Value(mib)]));
     CTLTYPE_STRING : Writeln(Format('%s.%-18s %s',[CTL_NAMES[CTL_VM].ctl_name, CTL_VM_NAMES[i].ctl_name, GetsysctlStrValue(mib)]));
    end;
 end;
 Writeln;
end;

begin
  try
    ListKernelValues;
    ListGenericCPU_IO_Values;
    ListUserLevelValues;
    ListVMValues;
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.