aiopxlib.html

Vxworks API操作系统和驱动程序设计API。压缩的HTML文件

</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine initializes the AIO library.  It should be called only
once after the I/O system has been initialized.  <i>lioMax</i> specifies the 
maximum number of outstanding <b><a href="./aioPxLib.html#lio_listio">lio_listio</a>(&nbsp;)</b> calls at one time.  If <i>lioMax</i>
is zero, the default value of <b>AIO_CLUST_MAX</b> is used.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
OK if successful, otherwise ERROR.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
<b>S_aioPxLib_IOS_NOT_INITIALIZED</b>
<p>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./aioPxLib.html#top">aioPxLib</a></b>

<hr>
<a name="aio_read"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>aio_read(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>aio_read(&nbsp;)</strong> - initiate an asynchronous read (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>int aio_read
    (
    struct aiocb * pAiocb     /* AIO control block */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine asynchronously reads data based on the following parameters
specified by members of the AIO control structure <i>pAiocb</i>.  It reads
<b>aio_nbytes</b> bytes of data from the file <b>aio_fildes</b> into the buffer
<b>aio_buf</b>.
<p>
The requested operation takes place at the absolute position in the file
as specified by <b>aio_offset</b>.
<p>
<b>aio_reqprio</b> can be used to lower the priority of the AIO request; if
this parameter is nonzero, the priority of the AIO request is
<b>aio_reqprio</b> lower than the calling task priority.
<p>
The call returns when the read request has been initiated or queued to the
device.  <b><a href="./aioPxLib.html#aio_error">aio_error</a>(&nbsp;)</b> can be used to determine the error status and of the
AIO operation.  On completion, <b><a href="./aioPxLib.html#aio_return">aio_return</a>(&nbsp;)</b> can be used to determine the
return status.
<p>
<b>aio_sigevent</b> defines the signal to be generated on completion 
of the read request.  If this value is zero, no signal is generated. 
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
OK if the read queued successfully, otherwise ERROR.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EBADF, EINVAL
<p>
</blockquote><h4>INCLUDE FILES</h4><blockquote><p>
<b>aio.h</b>
<p>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./aioPxLib.html#top">aioPxLib</a></b>, <b><a href="./aioPxLib.html#aio_error">aio_error</a>(&nbsp;)</b>, <b><a href="./aioPxLib.html#aio_return">aio_return</a>(&nbsp;)</b>, <b><a href="./ioLib.html#read">read</a>(&nbsp;)</b>

<hr>
<a name="aio_write"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>aio_write(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>aio_write(&nbsp;)</strong> - initiate an asynchronous write (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>int aio_write
    (
    struct aiocb * pAiocb     /* AIO control block */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine asynchronously writes data based on the following parameters
specified by members of the AIO control structure <i>pAiocb</i>.  It writes
<b>aio_nbytes</b> of data to the file <b>aio_fildes</b> from the buffer <b>aio_buf</b>.
<p>
The requested operation takes place at the absolute position in the file
as specified by <b>aio_offset</b>.
<p>
<b>aio_reqprio</b> can be used to lower the priority of the AIO request; if
this parameter is nonzero, the priority of the AIO request is
<b>aio_reqprio</b> lower than the calling task priority.
<p>
The call returns when the write request has been initiated or queued to
the device.  <b><a href="./aioPxLib.html#aio_error">aio_error</a>(&nbsp;)</b> can be used to determine the error status and of
the AIO operation.  On completion, <b><a href="./aioPxLib.html#aio_return">aio_return</a>(&nbsp;)</b> can be used to determine
the return status.
<p>
<b>aio_sigevent</b> defines the signal to be generated on completion 
of the write request.  If this value is zero, no signal is generated. 
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
OK if write queued successfully, otherwise ERROR.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EBADF, EINVAL
<p>
</blockquote><h4>INCLUDE FILES</h4><blockquote><p>
<b>aio.h</b>
<p>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./aioPxLib.html#top">aioPxLib</a></b>, <b><a href="./aioPxLib.html#aio_error">aio_error</a>(&nbsp;)</b>, <b><a href="./aioPxLib.html#aio_return">aio_return</a>(&nbsp;)</b>, <b><a href="./ioLib.html#write">write</a>(&nbsp;)</b>

<hr>
<a name="lio_listio"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>lio_listio(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>lio_listio(&nbsp;)</strong> - initiate a list of asynchronous I/O requests (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>int lio_listio
    (
    int               mode,   /* LIO_WAIT or LIO_NOWAIT */
    struct aiocb *    list[], /* list of operations */
    int               nEnt,   /* size of list */
    struct sigevent * pSig    /* signal on completion */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine submits a number of I/O operations (up to <b>AIO_LISTIO_MAX</b>)
to be performed asynchronously.  <i>list</i> is a pointer to an array of 
<b>aiocb</b> structures that specify the AIO operations to be performed.  
The array is of size <i>nEnt</i>.   
<p>
The <b>aio_lio_opcode</b> field of the <b>aiocb</b> structure specifies the AIO
operation to be performed.  Valid entries include <b>LIO_READ</b>, <b>LIO_WRITE</b>, and
<b>LIO_NOP</b>.  <b>LIO_READ</b> corresponds to a call to <b><a href="./aioPxLib.html#aio_read">aio_read</a>(&nbsp;)</b>, <b>LIO_WRITE</b>
corresponds to a call to <b><a href="./aioPxLib.html#aio_write">aio_write</a>(&nbsp;)</b>, and <b>LIO_NOP</b> is ignored.
<p>
The <i>mode</i> argument can be either <b>LIO_WAIT</b> or <b>LIO_NOWAIT</b>.  If <i>mode</i> is 
<b>LIO_WAIT</b>, <b><a href="./aioPxLib.html#lio_listio">lio_listio</a>(&nbsp;)</b> does not return until all the AIO operations 
complete and the <i>pSig</i> argument is ignored.  If <i>mode</i> is <b>LIO_NOWAIT</b>, the 
<b><a href="./aioPxLib.html#lio_listio">lio_listio</a>(&nbsp;)</b> returns as soon as the operations are queued.  In this case, 
if <i>pSig</i> is not NULL and the signal number indicated by
<b>pSig->sigev_signo</b> is not zero, the signal <b>pSig->sigev_signo</b> is
delivered when all requests have completed.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
OK if requests queued successfully, otherwise ERROR.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EINVAL, EAGAIN, EIO
<p>
</blockquote><h4>INCLUDE FILES</h4><blockquote><p>
<b>aio.h</b>
<p>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./aioPxLib.html#top">aioPxLib</a></b>, <b><a href="./aioPxLib.html#aio_read">aio_read</a>(&nbsp;)</b>, <b><a href="./aioPxLib.html#aio_write">aio_write</a>(&nbsp;)</b>, <b><a href="./aioPxLib.html#aio_error">aio_error</a>(&nbsp;)</b>, <b><a href="./aioPxLib.html#aio_return">aio_return</a>(&nbsp;)</b>.

<hr>
<a name="aio_suspend"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>aio_suspend(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>aio_suspend(&nbsp;)</strong> - wait for asynchronous I/O request(s)  (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>int aio_suspend
    (
    const struct aiocb *    list[], /* AIO requests */
    int                     nEnt,   /* number of requests */
    const struct timespec * timeout /* wait timeout */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine suspends the caller until one of the following occurs:
<ul>

<li>at least one of the previously submitted asynchronous I/O operations</li>
referenced by <i>list</i> has completed,
<li>a signal interrupts the function, or</li>
<li>the time interval specified by <i>timeout</i> has passed</li>
(if <i>timeout</i> is not NULL).
</ul>

<p>

</blockquote><h4>RETURNS</h4><blockquote><p>
OK if an AIO request completes, otherwise ERROR.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EAGAIN, EINTR  
<p>
</blockquote><h4>INCLUDE FILES</h4><blockquote><p>
<b>aio.h</b>
<p>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./aioPxLib.html#top">aioPxLib</a></b>

<hr>
<a name="aio_error"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>aio_error(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>aio_error(&nbsp;)</strong> - retrieve error status of asynchronous I/O operation (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>int aio_error
    (
    const struct aiocb * pAiocb /* AIO control block */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine returns the error status associated with the I/O operation 
specified by <i>pAiocb</i>.  If the operation is not yet completed, the error 
status will be EINPROGRESS.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
<p>
&nbsp;EINPROGRESS&nbsp;if&nbsp;the&nbsp;AIO&nbsp;operation&nbsp;has&nbsp;not&nbsp;yet&nbsp;completed,<br>
&nbsp;OK&nbsp;if&nbsp;the&nbsp;AIO&nbsp;operation&nbsp;completed&nbsp;successfully,<br>
&nbsp;the&nbsp;error&nbsp;status&nbsp;if&nbsp;the&nbsp;AIO&nbsp;operation&nbsp;failed,&nbsp;<br>
&nbsp;otherwise&nbsp;ERROR.
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EINVAL
<p>
</blockquote><h4>INCLUDE FILES</h4><blockquote><p>
<b>aio.h</b>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./aioPxLib.html#top">aioPxLib</a></b>

<hr>
<a name="aio_return"></a>
<p align=right>
<a href="rtnIndex.htm"><i>OS Libraries :  Routines</i></a></p>

</blockquote><h1>aio_return(&nbsp;)</h1> <blockquote></a></blockquote><h4>NAME</h4><blockquote>  
<p><strong>aio_return(&nbsp;)</strong> - retrieve return status of asynchronous I/O operation (POSIX)</p>

</blockquote><h4>SYNOPSIS</h4><blockquote><p>
<pre>size_t aio_return
    (
    struct aiocb * pAiocb     /* AIO control block */
    )
</pre>

</blockquote><h4>DESCRIPTION</h4><blockquote><p>
This routine returns the return status associated with the I/O operation
specified by <i>pAiocb</i>.  The return status for an AIO operation is the 
value that would be returned by the corresponding <b><a href="./ioLib.html#read">read</a>(&nbsp;)</b>, <b><a href="./ioLib.html#write">write</a>(&nbsp;)</b>, or 
<b>fsync(&nbsp;)</b> call.  <b><a href="./aioPxLib.html#aio_return">aio_return</a>(&nbsp;)</b> may be called only after the AIO operation
has completed (<b><a href="./aioPxLib.html#aio_error">aio_error</a>(&nbsp;)</b> returns a valid error code--not EINPROGRESS).
Furthermore, <b><a href="./aioPxLib.html#aio_return">aio_return</a>(&nbsp;)</b> may be called only once; subsequent 
calls will fail.
<p>
</blockquote><h4>RETURNS</h4><blockquote><p>
The return status of the completed AIO request, or ERROR. 
<p>
</blockquote><h4>ERRNO</h4><blockquote><p>
EINVAL, EINPROGRESS
<p>
</blockquote><h4>INCLUDE FILES</h4><blockquote><p>
<b>aio.h</b>
</blockquote><h4>SEE ALSO</h4><blockquote><p>
<b><a href="./aioPxLib.html#top">aioPxLib</a></b>

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