Re: else ladders practice

On 25/11/2024 03:17, Keith Thompson wrote:

Bart <bc@freeuk.com> writes:

On 24/11/2024 21:45, Keith Thompson wrote:

Bart <bc@freeuk.com> writes:

[...]

A more useful installation would of course need more standard headers,
an assembler, linker, and whatever .a files are needed to provide the
standard library.

Sure, those are all part of a C implementation, though they're not
part of gcc.

>
This seems to be a thing with Linux, where a big chunk of a C
implementation is provided by the OS.

 I'm not sure what you mean by "provided by the OS".  Linux-based
systems tend to be very modular, with almost everything provided by
some installable binary package.  Some of those packages have to
be provided by default, for example any dynamic libraries relied
on by most executables.  Files that are needed for development,
such as header files, compilers, and associated tools such as
assemblers and linkers, may be optional.

Well, does a C compiler for Linux come with its own stdio.h, or does it share /usr/include/stdio.h along with other compilers?
C compilers for Windows tend to be self-contained. Except for clang (see below). So each has its own stdio.h.
The only thing the OS provides is msvcrt.dll, a library of C standard functions, one which probably started out for internal use but too many programs now rely on it.

 

That is, standard headers, libraries, possibly even 'as' and 'ld'
utilities.

 On my system (Ubuntu), the as and ld commands are provided by the
binutils package ("binutils-x86-64-linux-gnu").  Some distributions
may install these by default.  Others do not, but they're easy
to install.
 

            On Windows, C compilers tend to be self-contained (except
for Clang which appears to be parasitical: it used to piggy-back onto
gcc, then it switched to MSVC).

 I don't know what you mean by "piggy-back onto gcc".

It relies for things like header files, linkers and libraries on an existing gcc installation.
I used clang for 18 months before I realised this.
Then they changed over to relying on MSVC for those facilities. This is when it started having trouble finding and syncing to MSVC, even when I had a working CL compiler.

 

I'm not sure what the utility to compile C programs is called, if it
is not 'gcc'. But this is a C group, I would expect people to know it
is a C compiler, or the front end of one.
>
However I use 'gcc' in other forums and everyone knows what I mean.
>
What do /you/ call the C compiler that is invoked by gcc?

 I call it gcc.
 "gcc" is the name for several things.  It's the "GNU Compiler
Collection".  It's the command invoked as the driver for any of
several compilers that are part of the GNU Compiler Collection.
It can refer specifically to the C compiler.  It's mildly confusing
for historical reasons, but most people don't have much of a
problem with it, and don't pretend that it's more confusing than
it really is.

But you seem to like pointing out that gcc doesn't include header files, assemblers, linkers and libraries. And previously you claimed that:
  "gcc by itself can't compile hello.c to hello.s."
So, what does it need? Is your point that it invokes a separate program like 'cc1.exe'? (Plus those 3 other binaries I listed in the case of tdm.)
You also said:
"You can't compile hello.c to hello.s without an OS kernel"
I guess you mean that it needs on OS to provide a file system, means to launch an executable like gcc.exe in the first place, and a display for messages?
That's a rather silly one. (However my first compiler did run on bare metal!)
 >>And hello.s isn't useful without an assembler, which is not treated as part of gcc
I deliberately stopped at the assembly file because I knew you would leap at that.
I assume that turning a .c file into .s/.asm is the very definition of what a baseline C compiler is expected to do.
It seems you are still disputing this and casting confusing. C compilers for Windows such as lccwin32, Pelles C, DMC, tcc, my mcc/cc are all self-contained and can turn hello.c all the way to hello.exe.
It is gcc that is always the exception, in every way (like generating a.exe files by default, or thinking that HELLO.C must be a C++ file).