smarteist / c-weak-lib

C Bug case

What is this?!

this code and configuration shows how a weak C library can be a bullet to your foot and change memory data collaterally!

Our weak library changes x and y variables together without any error or warning, that shows we should have a very good understanding about memory and it's L/R Values!

What happens in memory?

First, we have x and y, each of which uses 1B of memory as a character.

L Val	R Val
...	...
-------	-------
&8000	0x61
-------	-------
&8001	0x62
-------	-------
&8002	0x00
&8003	0x00
...	...

After executing f() we actually assign x=0x00003B29. That affects 4B of memory, and also written on y, as you can see the C linker doesn't care!

L Val	R Val
...	...
-------	-------
&8000	0x29
&8001	0x3b
&8002	0x00
&8003	0x00
-------	-------
...	...