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Date: Wed, 30 Jul 2014 17:09:06 +0200
From: Jens Gustedt <jens.gustedt@...ia.fr>
To: musl@...ts.openwall.com
Subject: regoff_t is broken

Hi,
perhaps I have missed a discussion on that.

commit 8327ae0cb23b799bc55a45e0d4bd95f5a2b1cdf1

breaks ABI compatibility with glibc for regexp on x86_64 architectures
by privileging i386.

To summarize the situation,

 - POSIX wants ptrdiff_t or ssize_t for this
 - glibc has int, which happens to be a compliant type on i386, but
    not on x86_64.
 - previously musl had long which works on x86_64 and breaks ABI with
   glibc on i386.
 - now musl has _Addr which is POSIXLY ok on i386 but breaks glibc ABI
   on x86_64.

I wonder if there are no other ways around this.

Also, I think there should be big flash lights somewhere that make
linking musl against a program that was compiled with glibc regex
impossible or so.

Unfortunately that broke my code in a way that was really hard to
trace. The musl type being wider than the glibc type, I got a
corrupted my stack somewhere near the start of my application. Did
cost me a day or so to find out where that came from.

Jens

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