user3879: I am looking for the source and/or proper definition for the int() function.
I have searched through the source in Arduino.app, without much success.
The reference gives a terse explanation 
int(x)
 x: a value of any type 
 Converts a value to the int data type

Passing 1, '1' or 49 returns the int 1. I haven't tested other types.
This seems to be an Arduino specific function - it doesn't seem to be in any c/c++ library.

user84: int(x) is not a function but another way to perform an explicit cast of x to an int. It is part of the C++ language itself, that is why you could not find it in a library.
This is not Arduino-specific.
In C and C++ you can cast a value to an int by doing this:
int y = (int) x;

C++ has extended this notation by allowing to do it this way, which is equivalent:
int y = int(x);

You can find this in more details in C++ language reference.

3879: <p>I am looking for the source and/or proper definition for the int() function.
I have searched through the source in Arduino.app, without much success.</p>

<p>The reference gives a terse explanation </p>

<pre><code>int(x)
 x: a value of any type 
 Converts a value to the int data type
</code></pre>

<p>Passing 1, '1' or 49 returns the int 1. I haven't tested other types.</p>

<p>This seems to be an Arduino specific function - it doesn't seem to be in any c/c++ library.</p>
 84: <p><code>int(x)</code> is not a function but <strong>another way to perform an explicit cast</strong> of <code>x</code> to an <code>int</code>. It is part of the C++ language itself, that is why you could not find it in a library.</p>

<p>This is not Arduino-specific.</p>

<p>In C and C++ you can cast a value to an int by doing this:</p>

<pre><code>int y = (int) x;
</code></pre>

<p><strong>C++</strong> has extended this notation by allowing to do it this way, which is equivalent:</p>

<pre><code>int y = int(x);
</code></pre>

<p>You can find this <a href="http://en.cppreference.com/w/cpp/language/explicit_cast" rel="nofollow">in more details</a> in C++ language reference.</p>
