Caché ObjectScript Reference - InterSystems Documentation

The num parameter can be a positive number, incrementing the value of the variable, or anegative number, decrementing the value of the variable. If you do not specify an increment,Caché uses the default increment of one (1).You can use the $GET function to return the current value of a variable.$INCREMENT performs this increment as an atomic operation, which does not require theuse of the LOCK command.If multiple processes simultaneously increment the same global through $INCREMENT,each process receives a unique, increasing number (or decreasing number if num is negative).In some situations, certain numbers may be skipped due to timing issues. For further detailson using $INCREMENT with global variables, see Using Multi-Dimensional Storage(Globals) in Using Caché Multi-Dimensional Storage.Caché does not restore the original, non-incremented value if $INCREMENT is in a transactionthat is rolled back.Incrementing Strings$INCREMENT is generally used for incrementing a variable containing a numeric value.However, it does accept a variable containing a string. The following rules apply when using$INCREMENT on a string:• A null string ("") is treated as having a value of zero.• A numeric string ("123" or "+0012.30") is treated as having that numeric value. Thestring is converted to canonical form: leading and trailing zeros and the plus sign areremoved.• A mixed numeric/nonnumeric string ("12AB" or "1,000") is treated as the numeric valueup to the first nonnumeric character and then truncated at that point. (Note that a commais a nonnumeric character.) The resulting numeric substring is converted to canonicalform: leading and trailing zeros and the plus sign are removed.• A nonnumeric string ("ABC" or "$12") is treated as having a value of zero.$INCREMENT• Exponent operations are performed. For example, if strvar="3E2", $INCREMENT treatsit as having a value of 300.• Arithmetic operations are not performed. For example, if strvar="3+7", $INCREMENTwill truncate the string at the plus sign (treating it as a nonnumeric character) and incrementstrvar to 4.Caché ObjectScript Reference 221