min(x, y)

Calculates the minimum of two numbers.

x: the first number, any data type

y: the second number, any data type

The smaller of the two numbers.

sensVal = min(sensVal, 100); // assigns sensVal to the smaller of sensVal or 100
                             // ensuring that it never gets above 100.

Perhaps counter-intuitively, max() is often used to constrain the lower end of a variable's range, while min() is used to constrain the upper end of the range.

Because of the way the min() function is implemented, avoid using other functions inside the brackets, it may lead to incorrect results

min(a++, 100);   // avoid this - yields incorrect results
 
a++;
min(a, 100);    // use this instead - keep other math outside the function

* max(x, y) * Constrain

Source: arduino.cc