trunc returns rounded value of <var> that is the nearest number value that is not larger as an absolute value than <var>.
In practice, it means that trunc() removes the decimal point, so for example trunc() applied to -2.6 will return -2 and applied to 2.6 will also return 2. However round() applied to -2.6 will return -3, and applied to 2.6 will return 3.
<var> is a number or a double and the result is a double.
