VERIFY

VERIFY returns a FIXED value indicating the position in x of the leftmost character that is not in y. It also allows you to specify the location within x at which to begin processing.

VERIFY(x,y,n)

x

Expression.x should have CHARACTER type, and if not, it is converted thereto.

y

Expression.y should have CHARACTER type, and if not, it is converted thereto.

n

Expression n specifies the location within x where processing begins.n should have FIXED type, and if not, it is converted thereto.

If all the characters in x do appear in y, a value of zero is returned. If x is the null string, a value of zero is returned. If x is not the null string andy is the null string, the value of n is returned. The default value for n is one.
n must be greater than 0 and no greater than 1 + LENGTH(x).
If n = LENGTH(x) + 1, the result is zero.