syswrite - Perldoc Browser

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If LENGTH is not specified, writes whole SCALAR. It bypasses buffered IO, so mixing this with reads (other than <code>sysread())</code>, <code>print</code>, <code>write</code>, <code>seek</code>, <code>tell</code>, or <code>eof</code> may cause confusion because the perlio and stdio layers usually buffer data. Returns the number of bytes actually written, or <code>undef</code> if there was an error (in this case the errno variable <code>$!</code> is also set). If the LENGTH is greater than the data available in the SCALAR after the OFFSET, only as much data as is available will be written.</p> <p>An OFFSET may be specified to write the data from some part of the string other than the beginning. A negative OFFSET specifies writing that many characters counting backwards from the end of the string. If SCALAR is of length zero, you can only use an OFFSET of 0.</p> <p><b>WARNING</b>: If the filehandle is marked <code>:utf8</code>, Unicode characters encoded in UTF-8 are written instead of bytes, and the LENGTH, OFFSET, and return value of syswrite() are in (UTF8-encoded Unicode) characters. The <code>:encoding(...)</code> layer implicitly introduces the <code>:utf8</code> layer. Alternately, if the handle is not marked with an encoding but you attempt to write characters with code points over 255, raises an exception. See <a href="/5.18.2/functions/binmode">"binmode"</a>, <a href="/5.18.2/functions/open">"open"</a>, and the <code>open</code> pragma, <a href="/5.18.2/open">open</a>.</p> </dd> </dl> </div> <div id="footer"> <p>Perldoc Browser is maintained by Dan Book (<a href="https://metacpan.org/author/DBOOK">DBOOK</a>). 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