How to determine kernel bitness in Mac OS X 10.6?

Question

I know that I can use the terminal and the system-profiler command to determine the current bitness of the kernel but I am trying to determine if there is a way to get that

Answer 1

You could use sysctlbyname. Dig around mach/machine.h to get possible values.

#include <mach/machine.h>
#include <sys/sysctl.h>

void example() 
{
   unsigned int cpuType;   
   size_t size = sizeof(cpuType);
   sysctlbyname("hw.cputype", &cpuType, &size, NULL, 0);

   bool is64 = cpuType & CPU_ARCH_ABI64;

   const char *cpu;

   switch (cpuType) {
      case CPU_TYPE_X86:
         cpu = "x86";
         break;
      case CPU_TYPE_X86_64:
         cpu = "x86_64";
         break;
      case CPU_TYPE_POWERPC:
         cpu = "ppc";
         break;
      case CPU_TYPE_POWERPC64:
         cpu = "ppc_64";
         break;
      case CPU_TYPE_SPARC:
         cpu = "sparc";
         break;
      default:
         cpu = "unknown";
         break;
   }
}

Answer 2

See man 3 uname: It fills a utsname structure which includes a member machine, which is "x86_64" or "i386" on Intel platforms:

struct utsname un;
int res = uname(&un);
if (res >= 0) {
    NSLog(@"%s", un.machine);
}

Answer 3

You should be able to read the system profiler information in from command line like this:

sys_profile = popen("system_profiler -xml", "r");

See the ProfileSystem example in Apple's documentation for how to parse it.

Software/System Software Overview/64-bit Kernel and Extensions is probably the key you want.