AMX NETLINX PROGRAMMING LANGUAGE, Руководство пользователя

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Language Elements
58 NetLinx Programming Language Reference Guide
ReadBuffer(Buffer,BufSize)
Can be used in an assignment statement such as:
Count = ReadBuffer(Buffer,BufSize)
or as part of an expression such as:
IF (ReadBuffer(Buffer,BufSize) > 0)
{
(* statements *)
}
The rules pertaining to calling parameters are the same for DEFINE_FUNCTION as they are for
DEFINE_CALL subroutines. The parameter list must appear in parentheses to the right of the function
name. If the function has no calling parameters a set of parentheses must still be included. For example,
MyFunc() // calling a function with no parameters
The return type may be omitted, as an alternate way of defining a subroutine. In this case the function
cannot be used as part of an expression or in an assignment statement.
DEFINE_FUNCTION also allows the use of the RETURN keyword that serves two purposes:
To return prematurely from a function.
To return a value from a function.
The format of the return statement is:
RETURN [<return value>]
If a return statement is encountered anywhere in the function, execution of the function is terminated
immediately and the value (if any) specified as the <return value> is returned to the caller.
A function that returns a value through the RETURN keyword must be declared with a return type.
Conversely, a function that is declared without a return type cannot return a value.
In the example below, GetBufferSize returns an unsigned 16-bit integer, BufSize.
The return type is indicated before the DEFINE_FUNCTION keyword.
DEFINE_FUNCTION INTEGER GetBufferSize()
LOCAL_VAR INTEGER BufSize = 0;
{
.
.
.
RETURN BufSize;
}
To call this function and to retrieve the RETURN value, use the following syntax:
BufSize = GetBufferSize()
where BufSize is declared to be of type INTEGER.
Even if a function returns a value, it is not necessary to assign the return value to a variable. Both forms
of the following call are valid. In the second case, the return value is simply thrown away.
Count = ReadBuffer(Buffer,BufSize)
ReadBuffer(Buffer,BufSize) // return value is ignored
The return type may only be one of the 8 intrinsic types (see Data Types). Strings,
arrays, structures, classes and other user-defined types may not be returned.