xCode 4.2如何检测程序在真机中的内存占用

#import <mach/mach.h>   void report_memory(void) {   struct task_basic_info info;   mach_msg_type_number_t size = sizeof(info);   kern_return_t kerr = task_info(mach_task_self(),                                  TASK_BASIC_INFO,                                  (task_info_t)&info,                                  &size);   if( kerr == KERN_SUCCESS ) {     NSLog(@"Memory used: %u", info.resident_size); //in bytes   } else {     NSLog(@"Error: %s", mach_error_string(kerr));   } }