[virgilp]

Linkers pretty much map data sections to memory, and in doing so are able to replace symbolic names (like global variables, or goto targets) with numbers. They may also completely drop some things that are not needed (e.g. code/files in a library that is never referenced).

I'm over-simplifying and also it's a bit incorrect, because there's also the loader that does a lot of the same work that linkers do, when loading the program in memory. So linkers don't actually produce the final image - but really, they're rather "simple" things (for some definition of "simple").

The hard-to-understand linker errors are typically caused by the compiler, not the linker (it's the compiler that speculatively chooses to use a symbol with a long and funny name, thinking that it'll later be provided by <somebody>, when in fact the linker later finds out that no library or object file actually provided said symbol; and then for the linker to give you a decent error message, it needs to have a pretty good understanding of what the compiler was actually trying to do - i.e. to know implementation details of the compiler that otherwise would not concern it at all).

[tester756]

>The hard-to-understand linker errors are typically caused by the compiler, not the linker (it's the compiler that speculatively chooses to use a symbol with a long and funny name, thinking that it'll later be provided by <somebody>, when in fact the linker later finds out that no library or object file actually provided said symbol; and then for the linker to give you a decent error message, it needs to have a pretty good understanding of what the compiler was actually trying to do - i.e. to know implementation details of the compiler that otherwise would not concern it at all).

So... maybe let's avoid having linker as another/external tool and just let compiler perform linking

[boricj]

The linker stitches object files together, regardless of their origin. If a compiler directly outputs a finalized artifact, then it would be impossible to add code written in other programming languages into the mix unless the compiler also doubles as a linker.

[tester756]

> then it would be impossible to add code written in other programming languages into

Is this really that important that we cannot skip this requirement?

[raddan]

You might be surprised how often multi-language programs appear. Basically all of modern day Python for starters. But also a number of important numerical libraries for C are actually written in Fortran.

[jay-barronville]

> You might be surprised how often multi-language programs appear. Basically all of modern day Python for starters. But also a number of important numerical libraries for C are actually written in Fortran.

In my experience, the most common use case is C-based programs with some C++ sprinkled in (especially if you need the C code to be compiled exclusively by a C compiler in order to maintain C semantics).

[tester756]

I thought it is done by ffi