ibm-information-center/dist/eclipse/plugins/i5OS.ic.apis_5.4.0.1/pase__memcpy_wt.htm

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<title>_MEMCPY_WT()--Copy Memory With Tags for i5/OS PASE</title>
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<h2>_MEMCPY_WT()--Copy Memory With Tags for i5/OS PASE</h2>
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<br>
&nbsp;&nbsp;Syntax
<pre>
#include &lt;as400_protos.h&gt;
void* _MEMCPY_WT(void *target,
const void *source,
size_t length);
void _MEMCPY_WT2(const ILEpointer *target,
const ILEpointer *source,
size_t length);
</pre>
<br>
&nbsp;&nbsp;Default Public Authority: *USE<br>
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&nbsp;&nbsp;Library: Standard C Library (libc.a)<br>
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&nbsp;&nbsp;Threadsafe: Yes<br>
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<p><strong>Note:</strong> These functions can only be used in an i5/OS PASE
program. See <a href="../rzalf/rzalfintro.htm">i5/OS PASE</a> for more
information about creating i5/OS PASE programs.</p>
<p>The _MEMCPY_WT() and _MEMCPY_WT2() functions copy memory without destroying
16-byte tagged pointers.</p>
<p>Standard memory copy functions such as memcpy never produce a usable tagged
pointer in the target memory. _MEMCPY_WT and _MEMCPY_WT2 copy memory in a way
that preserves the integrity of any complete (16-byte) tagged pointers copied,
as long as the source and target have the same alignment with respect to a
16-byte boundary.</p>
<br>
<h3>Parameters</h3>
<dl>
<dt><strong>target</strong></dt>
<dd>(Output) Pointer to target memory. For _MEMCPY_WT, target is the i5/OS
PASE address of the target memory. For _MEMCPY_WT2, target is the 16-byte
aligned address of a tagged space pointer to the target memory.<br>
<br>
</dd>
<dt><strong>source</strong></dt>
<dd>(Input) Pointer to source memory. For _MEMCPY_WT, source is the i5/OS PASE
address of the source memory. For _MEMCPY_WT2, source is the 16-byte aligned
address of a tagged space pointer to the source memory.<br>
<br>
</dd>
<dt><strong>length</strong></dt>
<dd>(Input) Specifies the number of bytes to copy between the source and
target.<br>
</dd>
</dl>
<br>
<h3>Authorities</h3>
<p>_MEMCPY_WT and _MEMCPY_WT2 require no authority.</p>
<br>
<h3>Return Value</h3>
<p>_MEMCPY_WT returns the target memory address. _MEMCPY_WT2 returns no
function result.</p>
<br>
<h3>Error Conditions</h3>
<p>Any error is reported with an i5/OS exception message that the system
converts to an i5/OS PASE signal. See <a href="pase_signals.htm">i5/OS PASE
Signal Handling</a> for information about handling i5/OS exceptions.</p>
<br>
<h3>Usage Notes</h3>
<ol>
<li>_MEMCPY_WT only copies between memory areas in the i5/OS PASE address
space. _MEMCPY_WT2 can copy between any memory areas addressable through tagged
space pointers, which need not be in the i5/OS PASE address space.<br>
<br>
</li>
<li>Memory is copied without error if the source and target do not have the
same alignment with respect to a 16-byte boundary or if only part of a tagged
pointer is copied, but the target will not contain a usable tagged pointer.<br>
<br>
</li>
<li>_MEMCPY_WT and _MEMCPY_WT2 are implemented with kernel system calls, so
they generally run slower than memcpy.<br>
<br>
</li>
</ol>
<br>
<h3>Related Information</h3>
<ul>
<li><a href="pase__cvtspp.htm">_CVTSPP()--Convert Space Pointer for i5/OS
PASE</a></li>
<li><a href="pase__setspp.htm">_SETSPP()--Set Space Pointer for i5/OS
PASE</a></li>
<li><a href="pase__setsppm.htm">_SETSPPM()--Set Multiple Space Pointers for i5/OS
PASE</a></li>
</ul>
<br>
<hr>
API introduced: V4R5
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