fs_reise@rcvie.at (Christian Reiser) (04/16/91)
Hi all, we usually develop our c++ programs on gnu g++ 1.37.1 and I am content with it. But there are others who think to change to AT&T C++ compiler, both compiling C++ language definition 2.0. Now I heard some roumors, that gnu's syntax checking is less strict than AT&T's. How much troubles besides the use of different libraries will it bring. Any experiences? Which compiler would you propose (but do not bother me with legal problems, I just have to estimate the technical adpect). Please e-mail. Thanks in advance Greetings from Vienna/Austria CR Christian Reiser Tel.: +431 39 16 21 / 247 Alcatel Austria-ELIN RC Fax.: +431 39 14 52 Ruthnergasse 1-7 E-mail: fs_reise@rcvie.at A-1210 Wien or: ...(!mcsun)!tuvie!rcvie!fs_reise Austria -- Greetings from Vienna/Austria CR Christian Reiser Tel.: +431 39 16 21 / 247
fs_reise@rcvie.at (Christian Reiser) (04/23/91)
For those, who have not read my previous posted question, I
asked for the differences between GNU's g++ 1.37.1 and AT&T's
C++ compiler both compiling C++ language definition 2.0.
(I was not interested in legal problems, because I just want
to estimate the technical aspects.)
By now I got 5 answers (thanks to all of them) and 4 questions
to post a summary (as I do now). Note, that I did not check
the statements, but just repost them.
* to port g++ to AT&T, just small things have to be changed.
* g++ accepts more, but nothing of them is realy importandt
(you just have to change it.) For instance: static variables
can be initialized directly in class definitions.
* g++ 1.37 has problems with multiple inheritance.
* In g++ 1.37 some minor bugs exist (local enums, ambigous
function declarations ...)
* the differences in syntax are not dificult, but the differences
in fstream are a real big problem.
* The preprocessor of g++ is ANSI, but AT&T's is not.
* On some machines, g++ executables are bigger.
* GNU's way of message passing is more efective and brings
advantages in execution speed. Here the part from GNU's manual:
* The naming convention of GNU C++ and AT&T C++ for overloaded functions
(and member functions) are incompatible. You cannot use AT&T C++
libraries with GNU C++. Even if the same naming convention were used,
you still would not want to use libraries compiled by the AT&T compiler.
Because the AT&T compiler is constrained to generate C code, there are
some things it cannot implement, such as the way GNU C++ passes objects
constructed on the stack. GNU C++ can also make most virtual function
calls take one or two memory references, while the AT&T compiler must
make 5 or 6 memory references to do the same thing. This efficiency has
its cost: if you want to link with AT&T code, compile it with GNU C++.
* GNU's error messages and especially debugging possibilies are
much better. AT&T sometimes only writes "syntax error line XXX".
* There is no source level debugging posibility at AT&T's.
* AT&T generates per default warnings, which g++ does not give like
- unreachable code (after return)
- function arguments not used
* For AT&T all include files have to be given, while g++ accepts
some missing "#include <...>" lines. (Perhaps because some
include files include others differently for both compilers.)
This is what I got till now. If you have any comments to this, do
not hesidate to e-mail me. If some interesting aspects occur, I
will post a second summary.
Again thanks to everybody who sent me his comments, I hope this
summary is some help for all.
Greetings from Vienna/Austria
CR
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| Christian Reiser | Tel.: +431 39 16 21 / 247 |
| Alcatel Austria - Elin RC | Fax.: +431 39 14 52 |
| Ruthnergasse 1-7, A-1210 Wien | E-mail: fs_reise@rcvie.at |
| Austria | or: ...(!mcsun)!tuvie!rcvie!fs_reise |
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--
Greetings from Vienna/Austria
CR
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