id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	difficulty
1005	mmap test doesn't correctly catch error situations	Christian Kellermann		"I have just came across this issue when dealing with a failed mmap FFI call. In this case mmap (The C function) will return a MAP_FAILED which is defined as (void*)-1 on linux and OpenBSD.

The mmap code checks for this by doing a (eq? -1 addr2). This is fine for 32 bit systems but not for 64 bit systems.

{{{
;; on 32 bit
#;2> (address->pointer -1)
#<pointer 0xffffffff>

;; on 64 bit
#;2> (address->pointer -1)
#<pointer 0x0>
#;3> (pointer->address #2)
1.84467440737096e+19
}}}

Note how the pointer printing code also gets it wrong. **this has been fixed in CHICKEN 5: it will now correctly print the pointer's address, interpreted as an unsigned number.**

A workaround would be to explicitly check for the -1 pointer representation:

{{{
(pointer=? (address->pointer -1) addr2)
}}}

This works but looks icky. I am not sure how to handle this right."	defect	reopened	major	someday	extensions			mmap ffi pointer suckage		medium