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devel / comp.lang.c / returning different sized ram elements by value - is it possible?

returning different sized ram elements by value - is it possible?

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Subject: returning different sized ram elements by value - is it possible?
From: profesor...@gmail.com (fir)
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by: fir - Sat, 5 Aug 2023 20:52 UTC

say i got a function and i want to return "diffarent size
ram elements" in there say

foo()
{
static char tab[100];
int n = rand()%10+1;
// return from adres &tab n bytes but by value -
}

i dont exactly remember how c returns structures by value
only remember some memcopy is involved

physically there should be possibility to use this mechanism to return n
bytes when n is chosen in runtime..though i doubt if c provides such syntax (becouse specifically in left side

x = foo()

i dont kno how to put undefined size object

Re: returning different sized ram elements by value - is it possible?

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From: chris.m....@gmail.com (Chris M. Thomasson)
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Subject: Re: returning different sized ram elements by value - is it possible?
Date: Sat, 5 Aug 2023 14:29:18 -0700
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by: Chris M. Thomasson - Sat, 5 Aug 2023 21:29 UTC

On 8/5/2023 1:52 PM, fir wrote:
> say i got a function and i want to return "diffarent size
> ram elements" in there say
>
> foo()
> {
> static char tab[100];
> int n = rand()%10+1;
> // return from adres &tab n bytes but by value -
> }
>
> i dont exactly remember how c returns structures by value
> only remember some memcopy is involved
>
> physically there should be possibility to use this mechanism to return n
> bytes when n is chosen in runtime..though i doubt if c provides such syntax (becouse specifically in left side
>
> x = foo()
>
> i dont kno how to put undefined size object

Check this out... One of my old region allocators might be of interest
to you, examples are stack based:

https://pastebin.com/raw/f37a23918

https://groups.google.com/g/comp.lang.c/c/7oaJFWKVCTw/m/sSWYU9BUS_QJ

Subject	Author
returning different sized ram elements by value - is it possible?	fir
Re: returning different sized ram elements by value - is it possible?	Chris M. Thomasson