ios获取可用和已用的内存

#import 

vm_size_t getUsedMemory() {
    task_basic_info_data_t 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) {
        return info.resident_size;
    } else {
        return 0;
    }
}

vm_size_t getFreeMemory() {
    mach_port_t host = mach_host_self();
    mach_msg_type_number_t size = sizeof(vm_statistics_data_t) / sizeof(integer_t);
    vm_size_t pagesize;
    vm_statistics_data_t vmstat;
    
    host_page_size(host, &pagesize);
    host_statistics(host, HOST_VM_INFO, (host_info_t) &vmstat, &size);
    
    return vmstat.free_count * pagesize;
}

NSInteger usedMemory = getUsedMemory();
NSInteger freeMemory = getFreeMemory();
    
NSLog(@"user memory: %zd", usedMemory);
NSLog(@"free memory: %zd", freeMemory);