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UNIX, C, Perl

Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C? Examples:
Network and internet access, access to UNIX interprocess controls and
communication, locale determination, EBCDIC/ASCII discrimination, etc.

Almost all of these are easy in Perl. Why isn't there a mechanism like
perl modules to allow easy extentions for facilities like these? Isn't
anyone working on this problem? or is it all being left for proprietary
systems?
Sep 2 '08 #1
223 7258
Pilcrow wrote:
Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C? Examples:
Network and internet access, access to UNIX interprocess controls and
communication, ...
They are not impossible in "ordinary C", they are impossible in strictly
conforming C. The C that operating systems are written in will make
heavy use of highly non-portable constructs that give access to all of
these things. In some cases, those non-portable constructs will consist
of calls to routines written in assembly language, or in-line assembly
language, but a very large fraction of the system can be written
entirely in non-portable C.
... locale determination, EBCDIC/ASCII discrimination, etc.
I'm not at all clear to me why you think that those can't be performed
in ordinary C. What features are you asking for that aren't provided by
<locale.h>? Perhaps if you described in more detail the desired
functionality I could address the question better.
Almost all of these are easy in Perl. Why isn't there a mechanism like
perl modules to allow easy extentions for facilities like these?
There are such mechanisms - they are called "header files" and
"libraries" , and together they serve a very similar purpose.
... Isn't
anyone working on this problem? or is it all being left for proprietary
systems?
There's no reasons why the libraries have to be proprietary, though many
certainly are.
Sep 2 '08 #2
Pilcrow wrote:
Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C? Examples:
Network and internet access, access to UNIX interprocess controls and
communication, locale determination, EBCDIC/ASCII discrimination, etc.

Almost all of these are easy in Perl. Why isn't there a mechanism like
perl modules to allow easy extentions for facilities like these? Isn't
anyone working on this problem? or is it all being left for proprietary
systems?
Should a programming language set standards for all
the application arenas in which it can be used?

--
Eric Sosman
es*****@ieee-dot-org.invalid
Sep 2 '08 #3

Eric Sosman <es*****@ieee-dot-org.invalidwrot e in message
news:2u******** *************** *******@comcast .com...
Pilcrow wrote:
Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C? Examples:
Network and internet access, access to UNIX interprocess controls and
communication, locale determination, EBCDIC/ASCII discrimination, etc.

Almost all of these are easy in Perl. Why isn't there a mechanism like
perl modules to allow easy extentions for facilities like these? Isn't
anyone working on this problem? or is it all being left for proprietary
systems?

Should a programming language set standards for all
the application arenas in which it can be used?
Sun Microsystems: "YOU BETCHA!!!"

Java, the Esperanto of computer programming languages...

---
William Ernest Reid
Sep 2 '08 #4

Pilcrow <pi*****@pp.inf owrote in message
news:11******** *************** *********@4ax.c om...
Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C? Examples:
Network and internet access, access to UNIX interprocess controls and
communication, locale determination, EBCDIC/ASCII discrimination, etc.

Almost all of these are easy in Perl. Why isn't there a mechanism like
perl modules to allow easy extentions for facilities like these? Isn't
anyone working on this problem? or is it all being left for proprietary
systems?
I thought "PERL" WAS coded in "C"...

Somebody, many people have worked on this "problem"; for example,
I got a "regex" PERL-like library for free with MY "C" compiler, along
with a bunch of other stuff, including stuff you mention...the only
people who haven't worked on it are those DAMN BEAURUCRATS
IN WASHINGTON!!! (or whever the "C" standards committee met,
and of course, their "portabilit y" yipping lap-dogs here)...

---
William Ernest Reid
Sep 2 '08 #5
On Sep 2, 10:18*am, "Bill Reid" <hormelf...@hap pyhealthy.netwr ote:
Pilcrow <pilc...@pp.inf owrote in message

news:11******** *************** *********@4ax.c om...
Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C? *Examples:
Network and internet access, access to UNIX interprocess controls and
communication, locale determination, EBCDIC/ASCII discrimination, etc.
Almost all of these are easy in Perl. Why isn't there a mechanism like
perl modules to allow easy extentions for facilities like these? *Isn't
anyone working on this problem? or is it all being left for proprietary
systems?

I thought "PERL" WAS coded in "C"...

Somebody, many people have worked on this "problem"; for example,
I got a "regex" PERL-like library for free with MY "C" compiler, along
with a bunch of other stuff, including stuff you mention...the only
people who haven't worked on it are those DAMN BEAURUCRATS
IN WASHINGTON!!! *(or whever the "C" standards committee met,
and of course, their "portabilit y" yipping lap-dogs here)...

---
William Ernest Reid
What are we considering "ordinary C?" Are we talking about the
libraries that are distributed with the GNU C library, any C compiler
that is POSIX standard supported, or are we talking about Visual C++?
The beauty of C is that it will run on damn near any piece of hardware
you throw at it. Almost every single platform's operating system is
written in a combination of C and (some form of) assembler. All of
these things that you mentioned are very possible, because frankly,
the language that you mentioned was implemented in C. The foundations
that you are building on were written in C, Pascal and assembler.

But here is the other interesting tidbit. Many languages that make it
easier for programmers to simply create a socket connection with two
lines of code (Python, C# and Java) have C libraries behind them doing
all the dirty work. If you really want to do all of these things in C
then your best bet is to follow a POSIX standard for sockets
(networking) and work strictly with C99 standards. You are almost
guaranteed that your code will run almost anywhere except certain
embedded platforms (and even those now are using POSIX compilers).

I am a firm believer that both C/C++ are portable as long as you have
someone in the background managing the projects. As long as the proper
libraries are used and standards are followed the code should be
relatively easy to port across platforms. But don't take my word for
it: there are many projects available at sourceforge.net that are open
source that can give you examples of a portable C application.
Although take a note: many "C" applications nowadays are essentially a
C++ application.
Sep 2 '08 #6
Bill Reid wrote:
....
IN WASHINGTON!!! (or whever the "C" standards committee met,
As you might expect for an international standards organization, the
meetings of ISO/IEC JTC1/SC22/WG14 are held in a wide variety of
places around the world. Judging from
<http://www.open-std.org/jtc1/sc22/wg14/www/meetings>, it would appear
that they have not met in Washington at any time since at least 1994,
and probably earlier. Since the US member is INCITS J11
<http://www.ncits.org/tc_home/j11.htm>, and that committee's meetings
are co-located with those of WG14, it doesn't look like Washington has
anything to do with this.
Sep 2 '08 #7
On 2 Sep 2008 at 11:48, Pilcrow wrote:
Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C?
Examples: Network and internet access, access to UNIX interprocess
controls and communication, locale determination, EBCDIC/ASCII
discrimination, etc.
You've spent too much time being brainwashed by the clc regulars.

ALL of these things are possible in C, OF COURSE. And if Official
Standards (peace be upon them) are really important to you, there's this
one you might have heard of: POSIX.

Sep 2 '08 #8
Pilcrow <pi*****@pp.inf owrites:
Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C? Examples:
Network and internet access, access to UNIX interprocess controls and
communication, locale determination, EBCDIC/ASCII discrimination, etc.

Almost all of these are easy in Perl. Why isn't there a mechanism like
perl modules to allow easy extentions for facilities like these? Isn't
anyone working on this problem? or is it all being left for proprietary
systems?
It depends on what you mean by "ordinary C".

The C language is defined by an ISO standard. (Actually by two
versions of the same ISO standard, since the most recent one has not
yet been widely implemented.) That standard specifically permits
extensions with certain limitations -- and many implementations
provide extensions without those limitations in a non-conforming mode.

If you want to write code that depends only on features defined in the
language standard, then your code will be portable to any conforming C
implementation -- but it won't be able to do networking, interprocess
communication, and so forth.

If you need to use such features, you can. You'll just have to use
some extension (such as POSIX) that's provided by your implementation.
Your program won't be portable to an implementation that doesn't
provide the particular extension(s) you're depending on, and in many
cases your program's behavior won't be defined by the language
standard.

This kind of tradeoff is unavoidable.

C is *designed* to allow writing non-portable code.

The thing is, though, that for most of the extensions you might want
to use, this newsgroup isn't the best place to discuss them. If you
want to ask how to use POSIX, there's comp.unix.progr ammer; for Win32,
there's comp.os.ms-windows.program mer.win32.

Don't confuse the scope of this newsgroup (as agreed upon by most of
the participants) with the scope of C programming.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
Sep 2 '08 #9
On Tue, 02 Sep 2008 12:04:38 GMT, James Kuyper <ja*********@ve rizon.net>
wrote:
>Pilcrow wrote:
>Given that UNIX, including networking, is almost entirely coded in C,
how come so many things are almost impossible in ordinary C? Examples:
Network and internet access, access to UNIX interprocess controls and
communicatio n, ...

They are not impossible in "ordinary C", they are impossible in strictly
conforming C. The C that operating systems are written in will make
heavy use of highly non-portable constructs that give access to all of
these things. In some cases, those non-portable constructs will consist
of calls to routines written in assembly language, or in-line assembly
language, but a very large fraction of the system can be written
entirely in non-portable C.
>... locale determination, EBCDIC/ASCII discrimination, etc.

I'm not at all clear to me why you think that those can't be performed
in ordinary C. What features are you asking for that aren't provided by
<locale.h>? Perhaps if you described in more detail the desired
functionalit y I could address the question better.
>Almost all of these are easy in Perl. Why isn't there a mechanism like
perl modules to allow easy extentions for facilities like these?

There are such mechanisms - they are called "header files" and
"libraries" , and together they serve a very similar purpose.
>... Isn't
anyone working on this problem? or is it all being left for proprietary
systems?

There's no reasons why the libraries have to be proprietary, though many
certainly are.
I am certainly glad to hear that these things are possible. But perhaps
an example of what I mean is appropriate. Last year I had a list of
several hundred addresses in the USA for which I wanted the 5+4 postal
zip codes. Using a standard module, 'WWW::Mechanize ', from CPAN
<http://en.wikipedia.or g/wiki/CPAN>, I was able, in about an hour, to
write a program (or a 'script'), in perl, that would access
<http://zip4.usps.com/zip4/welcome.jsp>, programmaticall y enter each
address, parse the response, extract the zip codes I needed, and update
my list.

The program I wrote is generalized enough to be able to do the same with
any other similar list. This saved me the chore of manually entering
each address into the form on that web page and copying and pasting the
zip code to my list. That chore would have taken several days, since I
am a clumsy typist, and the list, as I have said, has several hundred
entries.

How could I do the same sort of thing using C? Is there a repository of
libraries for C, similar to CPAN for Perl? If not, is anyone working on
it?

I am sure that it is possible, since Perl itself is written in standard
C, or at least GCC.
Sep 2 '08 #10

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