Posix shared memory problem
Dag-Erling Smørgrav
des at des.no
Tue May 12 10:55:41 UTC 2009
Lothar Scholz <scholz at scriptolutions.com> writes:
> Sujit K M <kmsujit at 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
--
Dag-Erling Smørgrav - des at des.no
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