Question: Is there any mechanism like destructors in C? Or is there another way to achieve it?

My requirement is that when a program terminates all memory allocated at runtime should be freed. I keep a list of memory that is allocated using `malloc`.

Answer: 
Another alternative is to write a memory manager.

The idea is that the memory manager allocates large blocks of memory and divides it into smaller pieces for the rest of the program to use. When the program terminates, the memory manager can just delete the large blocks.

That's the basic idea, although the memory manager may need to be more complex depending on the memory usage profile of the program.

There's a basic memory manager in the Doom source code you could examine: <http://doom.wikia.com/wiki/Zone_memory>
C++ uses RAII for managing resource lifetimes.  

There is no such mechanism in C, Since you cannot have member functions for structures. Your main concern should be freeing memory allocations for reuse during the lifetime of the program rather than at the end of the lifetime. Once the program ends the OS will reclaim the leaked memory anyways. 

Best way to do this in C is, to design your application to take care of lifetimes and code accordingly. This includes careful decision making of whether you really need dynamic memory allocations and if at all the lifetime of the allocated object should be well defined.