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 language' s "&" (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.