MocrHookFunction

This function allows you to attach or detach a user-defined function to an event when the specified font is used. A type of event to which a user-defined function can be hooked is string validation. This would immediately follow a read or verify operation. When this type of event occurs, the MocrReadString() or MocrVerifyString() function will call the hooked function one or many times during the operation to validate each string after it is read but before being written to the OCR result buffer. This function allows you to impose global string constraints, and can be used to implement custom checksum functions or to reject strings that would have otherwise met the character constraints imposed.

Note that a function hooked to an event executes on a distinct thread. This permits the functions to run asynchronously from the operation that fired the event and from functions hooked to another event.

Hooked functions should not take longer to execute than the period in which two of their associated events can occur. You cannot determine the instance of the event that fired the function, and even if this were possible, this information would generally not be very useful. Typically, a hooked function performs the minimum number of operations required and, if necessary, performs longer processes by launching other threads.