AMX NETLINX PROGRAMMING LANGUAGE, Руководство пользователя

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Language Elements
59 NetLinx Programming Language Reference Guide
Calling parameters
Parameters may be passed to any NetLinx function or subroutine. Calling parameters are simply
variables or constants that originate from the caller and are received by the function or subroutine being
invoked.
The NetLinx compiler passes all variables by reference . This means that the variable the subroutine
operates on is the same variable the caller passed. Any change made to a variable passed as a calling
parameter updates the value of the variable from the perspective of the caller. You can take advantage of
this
pass by reference feature to return an updated value through a calling parameter rather than as the
return value.
Constants, on the other hand, are passed by value . When this happens, a copy of the parameter is
delivered to the subroutine. Any change made to the variable representing the constant is lost once the
function or subroutine finishes.
Function and subroutine declarations must include the type and name of each parameter expected. If the
type is omitted, the default type is assumed; arrays are
CHAR
type and non-array parameters are
INTEGER
.
To specify an array as a function or subroutine parameter, one set of brackets for each array dimension
must follow the variable name, as shown in the following example:
DEFINE_CALL 'Process Array' (CHAR Array[ ][ ])
{
(* body of subroutine *)
}
The parameter
Array
is declared to be a 2-dimensional array, by including two sets of brackets after the
name. For compatibility with existing programs, the array dimensions may be specified inside the
brackets. These dimensions are not required and are ignored by the compiler. The NetLinx interpreter
will do bounds checking on the array and generate a run-time error if the array bounds are exceeded.
When calling a subroutine that takes an array as one of its parameters, pass only the name of the array as
the calling parameter, as shown below:
CHAR Buffer[10][20]
CALL 'Process Array' (Array)
If dimensions are specified in the call statement, the compiler will interpret that as specifying a subset of
the array. For example, suppose
Array
were defined as a 3-dimensional array. The third table of that
dimensional array could be passed to
'Process Array'
as follows:
CHAR Buffer[5][5][10]
CALL 'Process Array' (Array [3])