Dynamic memory allocation under the hood

I owed you some explanations regarding dynamic memory management implementation so here they are.

Before going into any specific implementation I would like to refer to Ritchie and Kernighan’s “The C programming languagebible. I had in hands the second edition published at Prentice Hall in 2008.

Chapter 8.7 provides a storage allocator example. Few important things are outlined out there:

    calls to malloc and free may occur in any order
    malloc requests storage from the operating system as needed
    the storage used by a program can be requested by malloc, but also by other sources, so its memory blocks are basically of three types: not owned by malloc, owned by malloc which are free and which are in use, only last two categories make the subject of our discussion (let’s name those two as free and in use)
    every free block is split into three fields as shown in the picture below: a pointer to the next free block, the size (usually in bytes) of the current free block and the actual stored data

What happens when mallocfunction is called?

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