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PR_CreateFileMap
================
Creates a file mapping object.
Syntax
------
.. code::
#include <prio.h>
PRFileMap* PR_CreateFileMap(
PRFileDesc *fd,
PRInt64 size,
PRFileMapProtect prot);
Parameters
~~~~~~~~~~
The function has the following parameters:
``fd``
A pointer to a :ref:`PRFileDesc` object representing the file that is to
be mapped to memory.
``size``
Size of the file specified by ``fd``.
``prot``
Protection option for read and write accesses of a file mapping. This
parameter consists of one of the following options:
- :ref:`PR_PROT_READONLY`. Read-only access.
- :ref:`PR_PROT_READWRITE`. Readable, and write is shared.
- :ref:`PR_PROT_WRITECOPY`. Readable, and write is private
(copy-on-write).
Returns
~~~~~~~
- If successful, a file mapping of type :ref:`PRFileMap`.
- If unsuccessful, ``NULL``.
Description
-----------
The ``PRFileMapProtect`` enumeration used in the ``prot`` parameter is
defined as follows:
.. code::
typedef enum PRFileMapProtect {
PR_PROT_READONLY,
PR_PROT_READWRITE,
PR_PROT_WRITECOPY
} PRFileMapProtect;
:ref:`PR_CreateFileMap` only prepares for the mapping a file to memory. The
returned file-mapping object must be passed to :ref:`PR_MemMap` to actually
map a section of the file to memory.
The file-mapping object should be closed with a :ref:`PR_CloseFileMap` call
when it is no longer needed.