user.exits.introduction Definition/General


Command user.exits.introduction Definition/General
Applicable release versions: R83, AP, AP 6.2, AP 6.1
Category General (155)
Description allows direct references to assembler routines known as "modes". These are generally not needed for new applications and are provided primarily for backwards compatibility and specialty utilities that must access internal structures.

The "unumber" syntax is the standard way to call pre-defined user exits. For available numbers, follow the "see also".

Users with assembly accounts may also enter their code via user exits. The standard way to do this is with the "u$" syntax which will jump directly into the mode called Every user exit call of this type requires an abs lookup.

On AP releases 6.1 and above, the user may initially use the "u?" syntax and store the result in a FlashBASIC or Pick/BASIC variable. This will NOT execute the user exit, but will return a direct pointer to its location. If null is returned, then the mode cannot be located. After this, the mode can be repeatedly called by using that variables value as the conversion. This is much faster than the "u$" syntax because no further abs lookups are needed.

On AP releases 6.2 and above, a numeric user exit which is not found in the user exit table is converted to a BASIC call to a subroutine named "U" followed by the number (like "u123"). If the system(0) function is executed at the beginning of this routine, it returns a 1 for an iconv() call or a 0 for an oconv() call.
Syntax unumber
Related access.user.exits