meaning of call by reference
1. call-by-reference An argument passing convention where the address of an argument variable is passed to a function or procedure, as opposed to where the value of the argument expression is passed. Execution of the function or procedure may have side-effects on the actual argument as seen by the caller. The C languages "&" address of and "*" dereference operators allow the programmer to code explicit call-by-reference. Other languages provide special syntax to declare reference arguments e. g. ALGOL 60. See also call-by-name, call-by-value, call-by-value-result. call-by-value CBV An evaluation strategy where arguments are evaluated before the function or procedure is entered. Only the values of the arguments are passed and changes to the arguments within the called procedure have no effect on the actual arguments as seen by the caller. See applicative order reduction, call-by-value-result, strict evaluation, call-by-name, lazy evaluation. call-by-value-result An argument passing convention where the actual argument is a variable V whose value is copied to a local variable L inside the called function or procedure. If the procedure modifies L, these changes will not affect V, which may also be in scope inside the procedure, until the procedure returns when the final value of L is copied to V. Under call-by-reference changes to L would affect V immediately. Used, for example, by BBC BASIC V on the Acorn Archimedes. call/cc call-with-current-continuation callee
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