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From: Richard Damon <richard@damon-family.org>
Newsgroups: comp.lang.c
Subject: Re: Regarding assignment to struct
Date: Sat, 3 May 2025 21:42:37 -0400
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On 5/2/25 2:34 PM, Lew Pitcher wrote:
> Back in the days of K&R, Kernighan and Ritchie published an addendum
> to the "C Reference Manual" titled "Recent Changes to C" (November 1978)
> in which they detailed some differences in the C language post "The
> C Programming Language".
> 
> The first difference they noted was that
>    "Structures may be assigned, passed as arguments to functions, and
>     returned by functions."
> 
>  From what I can see of the ISO C standards, the current C language
> has kept these these features. However, I don't see many C projects
> using them.
> 
> I have a project in which these capabilities might come in handy; has
> anyone had experience with assigning to structures, passing them as
> arguments to functions, and/or having a function return a structure?
> 
> Would code like
>    struct ab {
>      int a;
>      char *b;
>    } result, function(void);
> 
>    if ((result = function()).a == 10) puts(result.b);
> 
> be understandable, or even legal?
> 
> 

I will say that I have used the feature, but in very limited conditions, 
mostly where the structure is no bigger than one or two typical words.

It could be a structure with a bitfield to make accesses clearer than 
low level masking, or for a "point" with x and y tied into one object.

Bigger than that, and you likely want to pass the object by address, not 
by value, passing just a pointer to it.