comp.std.c Google Group

Re: function overloading

ja...@nospam.com (jacob navia) — Mon, 08 Sep 2008 06:47:43 UT

Well, this is funny. Imagine, overloading in assembler!
Who is going to dispatch? The assembler? That would be
*really* a smart assembler!
Obviously if you are not writing in C, you must use the fixed
interface and you can't use overloading. This is the same situation
as you have today. The advantage to C++ overloading is that

Re: function overloading

will...@wilbur.25thandclement.com (William Ahern) — Mon, 08 Sep 2008 05:36:00 UT

If you're trying to use the interface from assembler, libffi, C# P/Invoke,
or other similar methods, you can't use the overloaded interface, but must
instead use the type-specific routines.
The problem with opaque overloading is that you're precluded or hindered
from knowing the name and/or location of the procedure altogether, unless

Re: function overloading

wojte...@yahoo.ca (Wojtek Lerch) — Mon, 08 Sep 2008 01:08:39 UT

Yes you need to make sure that you avoid using them, but no you don't have
to know what exactly they are. They're just internal symbols used by the
library. Even without overloading, most non-trivial libraries do need to
reserve a chunk of the namespace for their internal symbols, and they
typically do that by documenting a single prefix rather than by listing all

Re: function overloading

jameskuy...@verizon.net — Mon, 08 Sep 2008 00:16:02 UT

It doesn't really matter if the mangling is done by the developer or
the compiler. Either way, the fundamental problem with name mangling
is pollution of the name space. If I'm using a third party library
that overloads my_sqrt(), don't I have to know what their mangled
names are (sqrti, sqrtC), and make sure that I avoid using them? In

Re: function overloading

ja...@nospam.com (jacob navia) — Sun, 07 Sep 2008 20:17:26 UT

Exactly
It will replace the my_sqrt function according to the actual
arguments given. If double it will call sqrt,
etc.
Maybe there are problems related to this method?
I do not think so.

Re: function overloading

z...@woaini.com (Lassie) — Sun, 07 Sep 2008 19:29:26 UT

"jacob navia" <ja...@nospam.com> schreef in bericht
So suppose I'm using a library using this overloaded function the compiler
can detect it and replace my_sqrt with the appropriate function? Maybe there
are problems related to this method?

Re: function overloading

will...@wilbur.25thandclement.com (William Ahern) — Sun, 07 Sep 2008 18:00:43 UT

Yet it missed the opportunity to expose intrinsics like GCC's
__builtin_choose_expr and __builtin_types_compatible_p, necessary for
implementing tgmath.h. Any name mangling would be done by the code authors,
not the compiler, leaving the status quo intact.
Alternatively, it could have standardized on GCC's compound expressions and

Re: function overloading

ja...@nospam.com (jacob navia) — Sun, 07 Sep 2008 17:45:31 UT

he C compiler lcc-win implements function overloading as an extension.
The often heared argument "It would require name mangling" can be
"casted away" with
double sqrt(double);
double sqrti(int);
double sqrtC(long double);
int overloaded my_sqrt(double) = sqrt;
int overloaded my_sqrt(int) = sqrti(int);

Re: function overloading

ja...@nospam.com (jacob navia) — Sun, 07 Sep 2008 17:45:00 UT

The C compiler lcc-win implements function overloading as an extension.
The often heared argument "It would require name mangling" can be
"casted away" with
double sqrt(double);
double sqrti(int);
double sqrtC(long double);
int overloaded my_sqrt(double) = sqrt;
int overloaded my_sqrt(int) = sqrti(int);

Re: function overloading

ks...@mib.org (Keith Thompson) — Sun, 07 Sep 2008 17:41:28 UT

C99 does have limited function overloading; see the <tgmath.h> header.
But it doesn't allow programmers to define their own overloaded
functions.

Re: function overloading

apoels...@supernova.home (Andrew Poelstra) — Sun, 07 Sep 2008 16:13:14 UT

Implementation complexity. It would require name-mangling, the
lack of which is an enormous boon to interfacing C with other
low-level languages (especially assemblers).

function overloading

z...@woaini.com (Lassie) — Sun, 07 Sep 2008 12:33:57 UT

Just curious, why is function overloading not in C? C99 added loads of
functions to deal with the different real types (sqrtf, sqrtl etc)but this
couldve been solved more elegantly with function overloading.
Whats the disadvantage of function overloading that I'm overlooking?

Re: Trigraphs forever

t...@login020.unx.sas.com (Tom Truscott) — Fri, 05 Sep 2008 16:13:28 UT

Yes, and it isn't just compilers which process such strings.
There are many trigraph-oblivious tools such as "yacc", "indent",
and of course locally-written tools such as one that gave heartburn
to my employer about 10 years ago:
[link]

Re: Please Explain Me About This Behaviour..,

pranav...@gmail.com (Pranav) — Sat, 06 Sep 2008 03:14:21 UT

NOTHING .., SORRY.., I JUST THOUGHT THE MEMBERS ARE DIFFERENT.., I
WILL TAKE CARE NEXT TIME..,

Re: Thoughts about the new standard

lawrence.jo...@siemens.com — Fri, 05 Sep 2008 21:00:51 UT

Originally, C allowed pretty much anything as the left operand, so the
distinction was quite necessary.