Re: [PROPOSAL] Builder, a build system integration for Emacs

[Gregory Heytings <gregory@heytings.org>]

>> This is the misconception I pointed to in my previous post: Rust 
>> libraries are not dynamic libraries, they are compiled into the 
>> program.  This eliminates all compatibility problems: you can have as 
>> many programs as you want on your computer, each one compiled with a 
>> different version of a given library.
>
> I have trouble understanding that.  Before dynamic libraries, we used 
> static libraries.  Each library was a .o file, made by compilation.
>

Rust libraries are neither dynamic (compiled separately and loaded at run 
time) nor static (compiled separately and linked at build time), they are 
always compiled together with the program.

>
> But how can each program have its own version of one and the same 
> library?  Does Rust store all libraries as **source code** and recompile 
> each library each time that library is linked into a program?
>

Yes, that's how it works.  For example, there are 25 versions of the 
"itoa" library (which does the opposite of the well-known "atoi" 
function), and you could have 25 different Rust programs on your computer, 
each one using on a different version of that library.  If you build these 
programs yourself, you will end up, in your local CARGO_HOME directory, 
with a copy of the source code of the 25 versions of that library: 
itoa-0.1.0, ..., itoa-1.0.6.