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Re: void

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On Sat, 16 Jul 2016 22:20:20 +0000, Stefan Ram wrote:

> On several occassions I have observed that the compiler, javac,
>   has it's own vocabulary. For example, it uses words like »context«
>   or »symbol« that might not be used this way in the JLS.
> 
>   Another example I encountered today:
> 
>   The JLS does not seem to think of »void« as a »type«. It says:
> 
> 8.4.5 Method Result
> 
> The result of a method declaration either declares the type of value
> that the method returns (the return type), or uses the keyword void to
> indicate that the method does not return a value.
> 
>   (end of quotation).
> 
>   But for the compiler, it seems to be a »type«:
> 
> Main.java:3: error: 'void' type not allowed here
> java.lang.System.out.println( java.lang.System.out.println() ); }}
>   
My guess is that the compiler does that because it has a single error 
message template, something like

%s:%d: error '%s' type not allowed here

so the least stupid thing it can use to describe the absence of arguments 
when they're expected is the work void which, in Java, always means an 
absence of an argument or return value.

This is unlike C, where a function declared as "void free(void ptr)" 
means that free() takes an untyped pointer and returns an untyped pointer 
value. BUT note the void as a return value is ambiguous in C because it 
can also mean that nothing is returned by a function.


-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |

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Re: void Martin Gregorie <martin@address-in-sig.invalid> - 2016-07-16 22:49 +0000
  Re: void Steven Simpson <ss@my.domain.invalid> - 2016-07-17 09:21 +0100
    Re: void Martin Gregorie <martin@address-in-sig.invalid> - 2016-07-17 18:36 +0000
      Re: void Steven Simpson <ss@my.domain.invalid> - 2016-07-17 20:17 +0100
        Re: void Martin Gregorie <martin@address-in-sig.invalid> - 2016-07-17 22:15 +0000
          Re: void Martin Gregorie <martin@address-in-sig.invalid> - 2016-07-17 22:26 +0000

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