Thread: Memory layers in c

Not sure I would call that "layers".

I'd call it "sections"....

Code is not stored in "data" - it is stored in "Code" or "Text" segment.

Data is used for global variables that have been given a value.
A special type of "data" section is used for other global variables - those that are set to zero by the runtime library. This section is usually called "bss".
The initialized data section is sometimes also split into a "const data" section and "modifiable data section" - so for example constants for printf() formats, string literals (char *str = "something") will be stored in a const region and can't be modified.

Stack is a section initialized by the "createprocess" or "createthread". It holds local variables and function return addresses [how to get back to where you came from when you call a function that calls a function that calls a function].

The heap is (in modern OS's) dynamic, that means that there is no heap at all until somene (part of the C runtime, usually) makes a call to the OS to get some memory for heap. The heap is managed by malloc/free and their close relatives (calloc, realloc for example).

The memory itself is no different for code, data, heap or stack - it's just plain memory, and the same memory can be used for any purpose.

Please ask further questions if you feel a need.

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Mats