Get the amount of free memory available in iPhone application

Today i was exploring memory leaks & debugging in Xcode and found a handy code! Get to now how much free memory available and how to free more memory.

#import <mach/mach.h>
#import <mach/mach_host.h>

+(natural_t) get_free_memory {
mach_port_t host_port;
mach_msg_type_number_t host_size;
vm_size_t pagesize;
host_port = mach_host_self();
host_size = sizeof(vm_statistics_data_t) / sizeof(integer_t);
host_page_size(host_port, &pagesize);
vm_statistics_data_t vm_stat;
if (host_statistics(host_port, HOST_VM_INFO, (host_info_t)&vm_stat, &host_size) != KERN_SUCCESS) {
NSLog(@"Failed to fetch vm statistics");
return 0;
/* Stats in bytes */
natural_t mem_free = vm_stat.free_count * pagesize;
return mem_free;

Call this static method inside your function to know how much memory is available. For example

>natural_t freemem = [YourClass get_free_memory]

Now you can free the memory using this code

/* Allocate the remaining amount of free memory, minus 2 megs * /
size_t size = freemem - 2048;
void *allocation = malloc(freemem - 2048);
bzero(allocation, size);

Looked at this application, the developer use this technique to free memory in a funny way and make $’s as well

I hope this will help someone icon smile Get the amount of free memory available in iPhone application

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My name is Adeem M Basraa. I am a software engineer from Lahore, PK. I’ve been involved in software development for nearly 4 years, with the last 1 year focused on application development for mobile devices (iPhone & Android).

2 Comments on "Get the amount of free memory available in iPhone application"

  1. Bob says:

    Hi Adeem,

    Thanks for this topic.
    Do you know how to get total size of disk and available space on it for iPhone ?


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