Date: Fri, 9 Sep 2011 18:27:41 -0400 (EDT) From: Benjamin Kaduk <kaduk@MIT.EDU> To: Lev Serebryakov <lev@freebsd.org> Cc: freebsd-current <freebsd-current@freebsd.org> Subject: Re: WITHOUT_GCC flag disables installation of /usr/bin/cpp too -- is it Ok? Message-ID: <alpine.GSO.1.10.1109091818060.1411@multics.mit.edu> In-Reply-To: <1997790603.20110907212004@serebryakov.spb.ru> References: <1231707981.20110907201053@serebryakov.spb.ru> <4E67A720.2000903@FreeBSD.org> <1997790603.20110907212004@serebryakov.spb.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
This message is in MIME format. The first part should be readable text,
while the remaining parts are likely unreadable without MIME-aware tools.
---559023410-274034473-1315607261=:1411
Content-Type: TEXT/PLAIN; charset=windows-1251; format=flowed
Content-Transfer-Encoding: QUOTED-PRINTABLE
On Wed, 7 Sep 2011, Lev Serebryakov wrote:
> Hello, Dimitry.
> You wrote 7 =F1=E5=ED=F2=FF=E1=F0=FF 2011 =E3., 21:17:20:
>
> I think, that /usr/bin/cpp is valuable by itself, as it is handy
> generic preprocessor tool, useful for preparing complex ipfw scripts,
> for example. All others are bundled together, for sure.
I am not really convinced. /usr/bin/cpp is the C preprocessor, and it is=
=20
only required to emit output that its bundled C compiler will accept as=20
input. In particular, it can do whatever it wants with whitespace,=20
wrapping and unwrapping lines, outputting other spurious text, &c..
From=20cpp(1):
The C preprocessor is intended to be used only with C, C++, and Obj=
ec-
tive-C source code. In the past, it has been abused as a general t=
ext
processor. It will choke on input which does not obey C's lexical
rules. For example, apostrophes will be interpreted as the beginni=
ng
of character constants, and cause errors. Also, you cannot rely on=
it
preserving characteristics of the input which are not significant t=
o
C-family languages. If a Makefile is preprocessed, all the hard ta=
bs
will be removed, and the Makefile will not work.
The (incredibly brain-dead) build system at $work runs cpp on a Makefile,=
=20
which I had to hack around in order to get things to work. It's really an=
=20
ugly hack, though, and is not at all robust. I wish I didn't have to.
If you want a general-purpose macro processor, please consider using=20
something that was designed as a general-purpose macro processor (e.g.=20
m4(1) which is in base) -- abusing cpp(1) is just asking for weird/subtle=
=20
errors to be introduce in the future.
-Ben Kaduk
>
> I think, it is good idea to exclude cpp from this list (but not from
> WITHOUT_TOOLCHAIN, of course).
---559023410-274034473-1315607261=:1411--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?alpine.GSO.1.10.1109091818060.1411>