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69 lines
1.8 KiB
ReStructuredText
69 lines
1.8 KiB
ReStructuredText
PR_OpenSharedMemory
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===================
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Opens an existing shared memory segment or, if one with the specified
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name doesn't exist, creates a new one.
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Syntax
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------
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.. code::
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#include <prshm.h>
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NSPR_API( PRSharedMemory * )
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PR_OpenSharedMemory(
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const char *name,
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PRSize size,
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PRIntn flags,
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PRIntn mode
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);
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/* Define values for PR_OpenShareMemory(...,create) */
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#define PR_SHM_CREATE 0x1 /* create if not exist */
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#define PR_SHM_EXCL 0x2 /* fail if already exists */
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Parameters
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~~~~~~~~~~
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The function has the following parameters:
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name
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The name of the shared memory segment.
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size
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The size of the shared memory segment.
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flags
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Options for creating the shared memory.
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mode
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Same as passed to :ref:`PR_Open`.
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Returns
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~~~~~~~
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Pointer to opaque structure ``PRSharedMemory``, or ``NULL`` if an error
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occurs. Retrieve the reason for the failure by calling :ref:`PR_GetError`
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and :ref:`PR_GetOSError`.
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Description
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-----------
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:ref:`PR_OpenSharedMemory` creates a new shared memory segment or
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associates a previously created memory segment with the specified name.
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When parameter ``create`` is (``PR_SHM_EXCL`` \| ``PR_SHM_CREATE``) and
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the shared memory already exists, the function returns ``NULL`` with the
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error set to ``PR_FILE_EXISTS_ERROR``.
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When parameter ``create`` is ``PR_SHM_CREATE`` and the shared memory
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already exists, a handle to that memory segment is returned. If the
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segment does not exist, it is created and a pointer to the related
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``PRSharedMemory`` structure is returned.
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When parameter ``create`` is 0, and the shared memory exists, a pointer
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to a ``PRSharedMemory`` structure is returned. If the shared memory does
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not exist, ``NULL`` is returned with the error set to
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``PR_FILE_NOT_FOUND_ERROR``.
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