Date: Wed, 10 Nov 2004 18:25:52 +0200 From: Andriy Gapon <avg@icyb.net.ua> To: gerarra@tin.it Cc: freebsd-hackers@freebsd.org Subject: Re: syscall: td_retval and zero return value Message-ID: <41924110.4000807@icyb.net.ua> In-Reply-To: <41536AD50005DCD2@ims3a.cp.tin.it> References: <41536AD50005DCD2@ims3a.cp.tin.it>
next in thread | previous in thread | raw e-mail | index | archive | help
on 10.11.2004 16:00 gerarra@tin.it said the following: > The way the handler advice you about syscalls failing is setting (and not > clearing as you were saying) the carry bit in eflags register (about ia32). > A sort of errno (if you see in a C-coder view) value is set in eax (or, > alternatively, edx) to show the reason of failing. There's no way to know > where error code is set; you can just verify pratically. I was actually interested in the opposite situation - something is put into eax,edx, but carry bit is cleared. > You can find all these things on "Programmers handbook". Thank you for the great hint! "The FreeBSD Developer's Handbook" has all. -- Andriy Gapon
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?41924110.4000807>