Re: C23 thoughts and opinions

On 26/05/2024 17:10, jak wrote:

David Brown ha scritto:

On 26/05/2024 15:46, jak wrote:

Michael S ha scritto:

On Sun, 26 May 2024 13:44:32 +0200
jak <nospam@please.ty> wrote:
>

Keith Thompson ha scritto:

jak <nospam@please.ty> writes:

Kaz Kylheku ha scritto:

On 2024-05-24, jak <nospam@please.ty> wrote:

Bonita Montero ha scritto:

Am 23.05.2024 um 21:49 schrieb Thiago Adams:

On 23/05/2024 16:25, Bonita Montero wrote:

I ask myself what the point is in further developing a
language like this that can actually no longer be saved.

do you mean C++?

>
No, C.

>
I think you have a lot of confusion about programming languages.
C and C++ are not comparable languages.

Except for observations like that we can write useful, production
software that compiles as C or C++, but go on ...

>
Indeed there are c++ compilers who, if used to compile c code,
could decide to call the c compiler to do the work, but if
something in the code is not strictly c, then the compilation will
be in c++, the size of the executable will increase significantly
and will need of an internal or external runtimer to work. If it
were the same thing you would not get different things.

>
Oh?  Do you know of a C++ compiler that actually behaves this way?
I've never heard of such a thing.
>
C and C++ are closely related, and C and C++ compilers often share
backends, but the two languages have different grammars.  The gcc
command, for example, can invoke either a C or C++ compiler, but it
knows which language it's compiling based on the source file name or
command line options, before it's even seen the content.
>
There are programs that are valid C and valid C++ but with different
behavior.  How would a compiler that behaves as you describe cope
with that?

>
For example g++ makes something similar: if you pass a file .C it
compile the C code but if the file (.C) contains C++ code then
compile C++.
>

>
No.
>

>
No, it does not.
g++ compiles as C++ unless you tell it to compile as C with '-x c'
option.
>

>
No.
>

>
>

>
You didn't read carefully or I didn't express myself well. I wrote that
the g++ compile c++ even if it is written inside a .c file.
However in doubt I preferred to try. If I pass to g++ a .c file that
contains c code, it compiles without any option, perhaps because it
reads as if it were c++ but in any case compiles it.
>

>
No.
>
>
The way gcc handles all this is actually quite straightforward.
>
First, there is no difference between the commands "gcc" and "g++" in the languages supported, or the way the language is determined.  The only difference between these two is the standard libraries linked by default when generating a final executable - "g++" automatically includes the C++ standard libraries, while "gcc" only has the C standard libraries.
>
In neither case does "gcc" or "g++" actually handle the compilation - these are driver front-ends that pass things on to the actual compilers, assemblers and linkers (and any other bits and pieces required).
>
The front-ends determine the language to use primarily from the suffix of the source file it is given.  ".c" files are compiled as C.  ".cpp", ".c++", ".cc", ".C" (note the capital C), ".cp", ".cxx", and ".CPP" are compiled as C++.  (There are many other extensions supported for different languages.)
>
The language choice can be overridden by using the "-x" switch, such as "-x c" or "-x c++".  The standard can be specified with "-std=".
>
There is no automatic detection of C or C++ based on the /content/ of the files.
>
>
<https://gcc.gnu.org/onlinedocs/gcc/Overall-Options.html>
>
>

 ?
I really wrote that something similar (similar != equal) did g++ and
that, if you write c++ code in a file with the .c extension, the g++
compile it. I never wrote that it was automatically recognized.
In addition, you just explained why g++ compile a .c that contains c++
code. I don't understand: no what?
 

I made an error here - "g++ foo.c" /will/ treat the file as C++.  I apologise for that, as it made things a lot more confusing.
But that is not what you wrote.  Perhaps you didn't write what you intended to write.  You said that g++ somehow determines whether to compile code as C or C++ based on the /contents/ of the file, not the filename suffix.  And that is completely wrong.
You also mixed up ".c" and ".C".  gcc considers ".c" to be C code, while ".C" (with a capital C) is considered C++.