From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <48B2A44F.3070001@domain.hid> Date: Mon, 25 Aug 2008 14:23:43 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <48B2994A.1050708@domain.hid> <48B2A0A3.5030308@domain.hid> <48B2A2B2.9070609@domain.hid> <48B2A3CE.1080205@domain.hid> In-Reply-To: <48B2A3CE.1080205@domain.hid> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-core] Native skin: user space handles sharable between processes? List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: xenomai-core Gilles Chanteperdrix wrote: > Jan Kiszka wrote: >> Gilles Chanteperdrix wrote: >>> Jan Kiszka wrote: >>>> Hi, >>>> >>>> what is the policy for the user space handles the native skin generates: >>>> Can the user share them between processes via putting them into shared >>>> memory (like it is allowed for some POSIX objects)? >>>> >>>> I'm wondering if I have to use the POSIX pattern to resolve the address >>>> of a fast mutex: If shared, look to global heap, otherwise use >>>> process-local heap. >>> The posix skin does only this only the first time. If the address is >>> local, it is computed and stored locally and never recomputed again. >> What remains is "if (shadow->attr.pshared) ...", so a condition + some >> bit in the shadow data structure. >> >> I could merged that bit into the lowest bit of the lock pointer, OK, but >> would still have to check for it. If native defines that a handle is >> only valid within the process that obtained it, I could skip that dance >> altogether. > > Ok. I understand what you mean. I wanted to work this around for the > POSIX API, but let us consider a real-life fact: the process-shared > objects are a corner-case. So, let us not spend too much sweat on it. $CUSTOMER will like that, too: I'm going the easy way. :) Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux