Difference and Histroy about inluding of header without h - c++

Rainer Heynke wrote:
> a friend of mine ask about the reason and the history beyond the two
> different ways to include std-headers like
>
> #include "stdio.h"
> #include <cstdio>
>
>
> He's no using the usenet, but he read the answers via google.

Standard headers are never included with quotes, always with angle
brackets. So, you shouldn't at all see

#include "stdio.h"

but always

#include <stdio.h>

.. As to the presence of '.h', it's specific to C. Standard C++ headers
do not have '.h' in them.

V
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Rainer Heynke wrote:


>
> He's no using the usenet, but he read the answers via google.

Google Groups allows one to post as well as read.




Brian

In article <gac1i1$hqc$1@aioe.org>, Rainer Heynke <noreply@plucked.de> wrote:

> Hi,
>
> a friend of mine ask about the reason and the history beyond the two
> different ways to include std-headers like
>
> #include "stdio.h"
> #include <cstdio>

Before C++ became an ISO standard, there were already many C++ headers
like iostream.h and similar, whose functionality differed from one
compiler to another. Rather than break code using pre-ISO headers or try
to find a backwards-compatible solution for every compiler's headers
(especially difficuly with the introduction of namespaces and everything
in std), they chose to use new names. Apparently extensionless names were
the least-conflicting, technically and politically. Keep in mind that
there is no requirement about how a compiler actually implements lines
like #include <iostream>; it might include the contents of a file named
"iostream", "iostream.cplusplustandardheader", "foobar", or might not
include a file at all, instead merely enabling use of the names contained
in it, whose implementation is internal to the compiler.

On Sep 12, 9:27 am, blargg....@gishpuppy.com (blargg) wrote:
> In article <gac1i1$hq...@aioe.org>, Rainer Heynke
> <nore...@plucked.de> wrote:

> > a friend of mine ask about the reason and the history beyond
> > the two different ways to include std-headers like

> > #include "stdio.h"
> > #include <cstdio>

> Before C++ became an ISO standard, there were already many C++
> headers like iostream.h and similar, whose functionality
> differed from one compiler to another.

Actually, the functionality differed less than the names. Some
compilers had <iostream.h>, <strstream.h>, etc.; others
<iostream.hpp>, <strstrea.hpp>, etc.; and who knows what else.

--
James Kanze (GABI Software) email:james.kanze@gmail.com
Conseils en informatique orientée objet/
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On Sep 11, 11:27 pm, Victor Bazarov <v.Abaza...@comAcast.net> wrote:
> Rainer Heynke wrote:
> > a friend of mine ask about the reason and the history beyond
> > the two different ways to include std-headers like

> > #include "stdio.h"
> > #include <cstdio>

> > He's no using the usenet, but he read the answers via
> > google.

> Standard headers are never included with quotes, always with
> angle brackets. So, you shouldn't at all see

> #include "stdio.h"

> but always

> #include <stdio.h>

> . As to the presence of '.h', it's specific to C. Standard
> C++ headers do not have '.h' in them.

Both <stdio.h> and <cstdio> are part of standard C++. Based on
the C++03 standard, very few compilers actuallly implement
<cstdio> correctly, however, so it's probably best to avoid it.

--
James Kanze (GABI Software) email:james.kanze@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34