user19838: Here are three use cases. Are all preferred or is the use of the F() macro pointless on some?
1.
Serial.println(F("some string"); // definitely useful here

2.
String str = F("some string");
Serial.println(str);

3.
int num = 5;
String str = F("some string with int ");
str += (String)num;
Serial.println(str);


user4143: Any time String is involved F() becomes pointless. Avoid String like the plague if you value your memory integrity.

19838: <p>Here are three use cases. Are all preferred or is the use of the <code>F()</code> macro pointless on some?</p>

<p><strong>1.</strong></p>

<pre><code>Serial.println(F("some string"); // definitely useful here
</code></pre>

<p><strong>2.</strong></p>

<pre><code>String str = F("some string");
Serial.println(str);
</code></pre>

<p><strong>3.</strong></p>

<pre><code>int num = 5;
String str = F("some string with int ");
str += (String)num;
Serial.println(str);
</code></pre>
 4143: <p>Any time String is involved F() becomes pointless. Avoid String like the plague if you value your memory integrity.</p>
