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>php_stream_seek</H1
><DIV
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></A
>php_stream_seek -- Reposition a stream</DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN252755"
></A
><H2
>Description</H2
>int <B
CLASS="methodname"
>php_stream_seek</B
> ( php_stream * stream, off_t offset, int whence )<BR
></BR
><P
> <B
CLASS="function"
>php_stream_seek()</B
> repositions the internal
position of <CODE
CLASS="parameter"
>stream</CODE
>.
The new position is determined by adding the <CODE
CLASS="parameter"
>offset</CODE
>
to the position indicated by <CODE
CLASS="parameter"
>whence</CODE
>.
If <CODE
CLASS="parameter"
>whence</CODE
> is set to <TT
CLASS="constant"
><B
>SEEK_SET</B
></TT
>,
<TT
CLASS="constant"
><B
>SEEK_CUR</B
></TT
> or <TT
CLASS="constant"
><B
>SEEK_END</B
></TT
> the offset
is relative to the start of the stream, the current position or the end of the stream, respectively.
</P
><P
> <B
CLASS="function"
>php_stream_seek()</B
> returns 0 on success, but -1 if there was an error.
</P
><DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>注意: </B
>
Not all streams support seeking, although the streams API will emulate a seek if
<CODE
CLASS="parameter"
>whence</CODE
> is set to <TT
CLASS="constant"
><B
>SEEK_CUR</B
></TT
>
and <CODE
CLASS="parameter"
>offset</CODE
> is positive, by calling <B
CLASS="function"
>php_stream_read()</B
>
to read (and discard) <CODE
CLASS="parameter"
>offset</CODE
> bytes.
</P
><P
> The emulation is only applied when the underlying stream implementation does not
support seeking. If the stream is (for example) a file based stream that is wrapping
a non-seekable pipe, the streams api will not apply emulation because the file based
stream implements a seek operation; the seek will fail and an error result will be
returned to the caller.
</P
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