Some thoughts about C and D, return data through parameters

[Petar]

On Tuesday, 19 December 2017 at 01:01:57 UTC, cosinus wrote:
> [snip]
>
> A second thought that came up was:
> Shouldn't there be a compiler-error if someone is ignoring the 
> return-value of a function?
>
> I saw this C-code:
>
> ```C
> (void)printf("Hello World!");
> ```
>
> It cast's the return-value to void to tell the compiler and 
> other programmer's that the return-value can be ignored.

Ignoring the return value is mainly useful when the primary use 
of the function are it's side effects, not it's return value. In 
many languages derived from C, people prefer using 'void' return 
types + exceptions for error handling.

It is an error to ignore the result of function with no side 
effects (D models such functions with the 'pure' attribute): 
https://dlang.org/spec/function.html#pure-functions