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80 lines
1.9 KiB
ReStructuredText
80 lines
1.9 KiB
ReStructuredText
PR_Writev
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=========
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Writes data to a socket from multiple buffers.
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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_Writev(
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PRFileDesc *fd,
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PRIOVec *iov,
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PRInt32 size,
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PRIntervalTime timeout);
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#define PR_MAX_IOVECTOR_SIZE 16
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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 for a socket.
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``iov``
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An array of ``PRIOVec`` structures that describe the buffers to write
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from.
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``size``
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Number of ``PRIOVec`` structures in the ``iov`` array. The value of
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this parameter must not be greater than ``PR_MAX_IOVECTOR_SIZE``. If
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it is, the function will fail and the error will be set to
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``PR_BUFFER_OVERFLOW_ERROR``.
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``timeout``
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A value of type :ref:`PRIntervalTime` describing the time limit for
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completion of the entire write operation.
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Returns
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~~~~~~~
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One of the following values:
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- A positive number indicates the number of bytes successfully written.
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- The value -1 indicates that the operation failed. The reason for the
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failure can be obtained by calling :ref:`PR_GetError`.
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Description
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-----------
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The thread calling :ref:`PR_Writev` blocks until all the data is written or
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the write operation fails. Therefore, the return value is equal to
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either the sum of all the buffer lengths (on success) or -1 (on
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failure). Note that if :ref:`PR_Writev` returns -1, part of the data may
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have been written before an error occurred. If the timeout parameter is
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not ``PR_INTERVAL_NO_TIMEOUT`` and all the data cannot be written in the
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specified interval, :ref:`PR_Writev` returns -1 with the error code
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``PR_IO_TIMEOUT_ERROR``.
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This is the type definition for ``PRIOVec``:
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.. code::
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typedef struct PRIOVec {
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char *iov_base;
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int iov_len;
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} PRIOVec;
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The ``PRIOVec`` structure has the following fields:
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``iov_base``
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A pointer to the beginning of the buffer.
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``iov_len``
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The size of the buffer.
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