iOS 获取 当前设备 可用内存 及当前 应用 所占内存

//
#import
#import
 


// 获取当前设备可用内存(单位：MB）
double)availableMemory
 {
 vm_statistics_data_t vmStats;
 mach_msg_type_number_t infoCount = HOST_VM_INFO_COUNT;
 kern_return_t kernReturn = host_statistics(mach_host_self(), 
                                            HOST_VM_INFO, 
                                            (host_info_t)&vmStats, 
                                           
 
 if (kernReturn != KERN_SUCCESS) {
   return NSNotFound;

 
 return ((vm_page_size *vmStats.free_count) / 1024.0) / 1024.0;
 }
 
// 获取当前任务所占用的内存（单位：MB）
double)usedMemory
 {
 task_basic_info_data_t taskInfo;
 mach_msg_type_number_t infoCount = TASK_BASIC_INFO_COUNT;
 kern_return_t kernReturn = task_info(mach_task_self(), 
                                      TASK_BASIC_INFO, 
                                      (task_info_t)&taskInfo, 
                                     
 
 if (kernReturn != KERN_SUCCESS
    
   return NSNotFound;

 
 return taskInfo.resident_size / 1024.0 / 1024.0;
 }