85 lines
2.4 KiB
ReStructuredText
85 lines
2.4 KiB
ReStructuredText
PR_Seek
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=======
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Moves the current read-write file pointer by an offset expressed as a
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32-bit integer.
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.. container:: blockIndicator deprecated deprecatedHeader
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| **Deprecated**
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| This feature is no longer recommended. Though some browsers might
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still support it, it may have already been removed from the
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relevant web standards, may be in the process of being dropped, or
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may only be kept for compatibility purposes. Avoid using it, and
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update existing code if possible; see the `compatibility
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table <#Browser_compatibility>`__ at the bottom of this page to
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guide your decision. Be aware that this feature may cease to work
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at any time.
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Deprecated in favor of :ref:`PR_Seek64`.
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Syntax
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~~~~~~
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.. code::
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#include <prio.h>
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PRInt32 PR_Seek(
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PRFileDesc *fd,
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PRInt32 offset,
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PRSeekWhence whence);
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Parameters
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~~~~~~~~~~
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The function has the following parameters:
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``fd``
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A pointer to a :ref:`PRFileDesc` object.
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``offset``
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A value, in bytes, used with the whence parameter to set the file
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pointer. A negative value causes seeking in the reverse direction.
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``whence``
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A value of type :ref:`PRSeekWhence` that specifies how to interpret the
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``offset`` parameter in setting the file pointer associated with the
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fd parameter. The value for the ``whence`` parameter can be one of
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the following:
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- :ref:`PR_SEEK_SET`. Sets the file pointer to the value of the
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``offset`` parameter.
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- :ref:`PR_SEEK_CUR`. Sets the file pointer to its current location
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plus the value of the ``offset`` parameter.
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- :ref:`PR_SEEK_END`. Sets the file pointer to the size of the file
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plus the value of the ``offset`` parameter.
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Returns
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~~~~~~~
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The function returns one of the following values:
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- If the function completes successfully, it returns the resulting file
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pointer location, measured in bytes from the beginning of the file.
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- If the function fails, the file pointer remains unchanged and the
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function returns -1. The error code can then be retrieved with
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:ref:`PR_GetError`.
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Description
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-----------
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Here's an idiom for obtaining the current location of the file pointer
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for the file descriptor ``fd``:
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``PR_Seek(fd, 0, PR_SEEK_CUR)``
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See Also
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--------
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If you need to move the file pointer by a large offset that's out of the
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range of a 32-bit integer, use :ref:`PR_Seek64`. New code should use
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:ref:`PR_Seek64` so that it can handle files larger than 2 GB.
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