Recent posts to Compare operands of type STRUCThttps://forge.codesys.com/forge/talk/Engineering/thread/e3d1208273/2020-02-27T13:52:51.889000ZRecent posts to Compare operands of type STRUCTCompare operands of type STRUCT2020-02-27T13:52:51.889000Z2020-02-27T13:52:51.889000ZPatrickThttps://forge.codesys.com/u/patrickt/https://forge.codesys.comb74bdd8f18a6dd824d83bed7d0808ac0ec65a694<div class="markdown_content"><p>Great, that's exactly what I need, thanks.</p></div>Compare operands of type STRUCT2020-02-27T13:52:51.704000Z2020-02-27T13:52:51.704000Zlearnetkhttps://forge.codesys.com/u/learnetk/https://forge.codesys.com14b19a75ec4fa74ec2b158475333075ecbc5fb89<div class="markdown_content"><p>Hi<br/>
not sure that you could still compare structure directly. But you could do it with pointers, using the Sysmemcmp function in library Sysmem. </p>
<div class="codehilite"><pre><span></span><span class="n">pstruct1</span><span class="o">:</span> <span class="n">POINTER</span> <span class="n">TO</span> <span class="n">BYTE</span><span class="o">;</span>
<span class="n">pstruct2</span><span class="o">:</span> <span class="n">POINTER</span> <span class="n">TO</span> <span class="n">BYTE</span><span class="o">;</span>
<span class="n">pstruct1</span> <span class="o">:=</span> <span class="n">ADR</span><span class="o">(</span><span class="n">struct1</span><span class="o">);</span>
<span class="n">pstruct2</span> <span class="o">:=</span> <span class="n">ADR</span><span class="o">(</span><span class="n">struct2</span><span class="o">);</span>
</pre></div>
<p>IF sysmemcmp(pstruct1,pstruct2, SIZEOF(struct1)) <> 0 THEN<br/>
testBool := TRUE;<br/>
ELSE<br/>
testBool := FALSE;<br/>
END_IF</p>
<p>something as above</p></div>Compare operands of type STRUCT2020-02-27T13:52:51.541000Z2020-02-27T13:52:51.541000ZPatrickThttps://forge.codesys.com/u/patrickt/https://forge.codesys.com8e329824ac719d6e347d0963deb961f6671a895f<div class="markdown_content"><p>The following Help section for Data Type > Structure implies that it is possible to compare structures: </p>
<p>"If the target system supports the data type, as from compiler version >= 3.5.7.0 you can compare operands of type STRUCT (structure). Example: IF (stStruct1 := stStruct2) THEN...." . </p>
<p>(I assume this is a typo and should read IF (struct1 = struct2) THEN ...)</p>
<p>Using Control Win V3 Version 3.5.7.10, I have:</p>
<p>TYPE TestDUT :<br/>
STRUCT<br/>
MyInt: INT;<br/>
END_STRUCT<br/>
END_TYPE</p>
<p>VAR<br/>
struct1: TestDUT;<br/>
struct2: TestDUT;<br/>
testBool: BOOL;<br/>
END_VAR</p>
<p>IF (struct1 = struct2) THEN<br/>
testBool := TRUE;<br/>
END_IF</p>
<p>This generates the error:<br/>
Cannot compare type 'TestDUT' with type 'TestDUT'</p>
<p>Have I made an error or is this feature not supported on the target system?</p></div>