Date: Tue, 12 May 2009 12:55:39 +0200 From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no> To: Lothar Scholz <scholz@scriptolutions.com> Cc: arch@freebsd.org, Sujit K M <kmsujit@gmail.com>, Garrett Wollman <wollman@bimajority.org> Subject: Re: Posix shared memory problem Message-ID: <86fxfa615g.fsf@ds4.des.no> In-Reply-To: <981850520.20090511172605@scriptolutions.com> (Lothar Scholz's message of "Mon, 11 May 2009 17:26:05 %2B0200") References: <mit.lcs.mail.freebsd-arch/588815840.20090509203115@scriptolutions.com> <mit.lcs.mail.freebsd-arch/20090509200724.GA25714@stack.nl> <200905100500.n4A50GOa050728@hergotha.csail.mit.edu> <7710650619.20090510075706@scriptolutions.com> <18950.63671.323324.756287@hergotha.csail.mit.edu> <1393224851.20090511112537@scriptolutions.com> <74fe56020905110410y430bf76yacf5c5a308a99865@mail.gmail.com> <981850520.20090511172605@scriptolutions.com>
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Lothar Scholz <scholz@scriptolutions.com> writes: > Sujit K M <kmsujit@gmail.com> writes: > > What needs to be fixed? Could you be more specific? > That the name argument is just that "a name" (in its own name space) > not a path. Allow me to quote from the SUSv3 again: DESCRIPTION The shm_open() function shall establish a connection between a shared memory object and a file descriptor. [...] The name argument points to a string naming a shared memory object. It is unspecified whether the name appears in the file system and is visible to other functions that take pathnames as arguments. The name argument conforms to the construction rules for a pathname. [...] RATIONALE [...] Note that such shared memory objects can actually be implemented as mapped files. In both cases, the size can be set after the open using ftruncate(). The shm_open() function itself does not create a shared object of a specified size because this would duplicate an extant function that set the size of an object referenced by a file descriptor. On implementations where memory objects are implemented using the existing file system, the shm_open() function may be implemented using a macro that invokes open(), and the shm_unlink() function may be implemented using a macro that invokes unlink(). [...] DES --=20 Dag-Erling Sm=C3=B8rgrav - des@des.no
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