C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  return 1; suggestion Goto page 1, 2  Next          C++Talk.NET Forum Index -> C++ language, library and standards View previous topic :: View next topic   Author Message Ioannis Vranos Guest Posted: Thu Apr 15, 2004 5:10 pm    Post subject: return 1; suggestion Now it may sound a bit stuoid in the beginning. I was talking with someone who was using return 1; in main() to signal errors because #include <cstdlib> return EXIT_FAILURE; is tiresome to write and also difficult for newbies to understand it. Wouldn't be better this to be added in the upcoming standard as a portable way ti signal error? Essentially return 1; to be equivalent to return EXIT_FAILURE; as return 0; is equivalent to return EXIT_SUCCESS; Ioannis Vranos --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Ben Hutchings Guest Posted: Thu Apr 15, 2004 7:48 pm    Post subject: Re: return 1; suggestion "Ioannis Vranos" wrote: Quote: Now it may sound a bit stuoid in the beginning. I was talking with someone who was using return 1; in main() to signal errors because #include return EXIT_FAILURE; is tiresome to write Oh, the agony. You only have to write it once per program. Quote: and also difficult for newbies to understand it. The #include may be obscure, but that's something that has to be learnt anyway. The named constant is surely helpful to "newbies" and others. It's not exactly obvious that 0 means success and 1 means failure; in fact it's the inverse of what one might expect. Quote: Wouldn't be better this to be added in the upcoming standard as a portable way ti signal error? Essentially return 1; to be equivalent to return EXIT_FAILURE; as return 0; is equivalent to return EXIT_SUCCESS; That might break a platform-specific C++ program that currently returns 1 on a platform where this doesn't indicate failure. For example, on VMS a return code of 1 indicates success. (I suspect that C++ implementations on VMS change a return code of 0 to 1 and vice versa, but this certainly isn't required.) --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top James Kuyper Guest Posted: Thu Apr 15, 2004 11:09 pm    Post subject: Re: return 1; suggestion [email]ivr (AT) guesswh (DOT) at.emails.ru[/email] ("Ioannis Vranos") wrote in message news:<c5m7ap$1f25$1 (AT) ulysses (DOT) noc.ntua.gr>... Quote: Now it may sound a bit stuoid in the beginning. I was talking with someone who was using return 1; in main() to signal errors because #include return EXIT_FAILURE; is tiresome to write and also difficult for newbies to understand it. He finds "return 1;" to be easier to understand than "return EXIT_FAILURE;"? The second clearly implies that you're exiting the program, and that something failed. I have no idea what a newbie would conclude from "return 1", but it's rather unlikely to match what I just wrote. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Loïc Joly Guest Posted: Thu Apr 15, 2004 11:25 pm    Post subject: Re: return 1; suggestion Ioannis Vranos wrote: Quote: Now it may sound a bit stuoid in the beginning. I was talking with someone who was using return 1; in main() to signal errors because #include return EXIT_FAILURE; is tiresome to write and also difficult for newbies to understand it. Wouldn't be better this to be added in the upcoming standard as a portable way ti signal error? Essentially return 1; to be equivalent to return EXIT_FAILURE; as return 0; is equivalent to return EXIT_SUCCESS; Well, I do agree the there is an inconsistency between the success and the failure case, and that this inconsistency can make learning C++ a (very) little bit more complex. My proposal would be just the opposite of yours : Just don't mandate any value for EXIT_SUCCESS. -- Loïc --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Ioannis Vranos Guest Posted: Fri Apr 16, 2004 12:59 am    Post subject: Re: return 1; suggestion "James Kuyper" <kuyper (AT) wizard (DOT) net> wrote Quote: ivr (AT) guesswh (DOT) at.emails.ru ("Ioannis Vranos") wrote in message news:<c5m7ap$1f25$1 (AT) ulysses (DOT) noc.ntua.gr>... Now it may sound a bit stuoid in the beginning. I was talking with someone who was using return 1; in main() to signal errors because #include <cstdlib return EXIT_FAILURE; is tiresome to write and also difficult for newbies to understand it. He finds "return 1;" to be easier to understand than "return EXIT_FAILURE;"? The second clearly implies that you're exiting the program, and that something failed. I have no idea what a newbie would conclude from "return 1", but it's rather unlikely to match what I just wrote. It is easier for a newbie to write return 1; rather than #include ... return EXIT_FAILURE; When you were newbie you were returning EXIT_FAILURE; in main() if you wanted to signal failure? Ioannis Vranos --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Niklas Matthies Guest Posted: Fri Apr 16, 2004 12:59 am    Post subject: Re: return 1; suggestion On 2004-04-15 23:09, James Kuyper wrote: : Quote: He finds "return 1;" to be easier to understand than "return EXIT_FAILURE;"? The second clearly implies that you're exiting the program, and that something failed. Actually, I tend to think that EXIT_FAILURE clearly implies a failure to exit (whatever is or was being attempted to be exited). ;) -- Niklas Matthies --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top James Kuyper Guest Posted: Fri Apr 16, 2004 3:28 pm    Post subject: Re: return 1; suggestion [email]ivr (AT) otenet (DOT) gr[/email] ("Ioannis Vranos") wrote in message news:<c5n7mn$qq9$1 (AT) ulysses (DOT) noc.ntua.gr>... Quote: "James Kuyper" <kuyper (AT) wizard (DOT) net> wrote in message news:8b42afac.0404151417.3383656a (AT) posting (DOT) google.com... [email]ivr (AT) guesswh (DOT) at.emails.ru[/email] ("Ioannis Vranos") wrote in message news:<c5m7ap$1f25$1 (AT) ulysses (DOT) noc.ntua.gr>... Now it may sound a bit stuoid in the beginning. I was talking with someone who was using return 1; in main() to signal errors because #include return EXIT_FAILURE; is tiresome to write and also difficult for newbies to understand it. He finds "return 1;" to be easier to understand than "return EXIT_FAILURE;"? The second clearly implies that you're exiting the program, and that something failed. I have no idea what a newbie would conclude from "return 1", but it's rather unlikely to match what I just wrote. It is easier for a newbie to write return 1; rather than #include .. return EXIT_FAILURE; When you were newbie you were returning EXIT_FAILURE; in main() if you wanted to signal failure? I started using EXIT_FAILURE as soon as I heard of it. That was so long ago that I can't remember whether it was part of the K&R C that I first learned, or was an ANSI innovation. If the latter, then it didn't come into existence until long after I was no longer a newbie. On the other hand, it was a long time before I realized that "return EXIT_FAILURE;" was somewhat better than "exit(EXIT_FAILURE);". I don't remember when I made that transition. You said it was "difficult for newbies to understand"; now you're arguing that it's difficult for them to write. Those two different things. I agree that a newbie might be unfamiliar with the EXIT_FAILURE macro; a newbie is equally likely to be unfamiliar with the (implementation-specific) fact that "return 1;" can be used for that same purpose. Howver, as far as understanding is concerned, rather than writing, EXIT_FAILURE is wonderfully self-expressive, and correspondingly easy to understand, making it far superior to '1'. It's also guaranteed to return an error status, which isn't true of '1'. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Dave Moore Guest Posted: Fri Apr 16, 2004 5:40 pm    Post subject: Re: return 1; suggestion snip Quote: It is easier for a newbie to write return 1; rather than #include <cstdlib .. return EXIT_FAILURE; When you were newbie you were returning EXIT_FAILURE; in main() if you wanted to signal failure? Hmmm ... I think the logic is backward here ... "easier" doesn't necessarily mean "better", *especially* for newbies. I agree with other posters that the named variable is far clearer, even if it involves a few more keystrokes. When I was a newbie, I understood the value of name-substitution (e.g. via typedef) for literals, long before I understood the (arbitrary) convention that <0> means "success" and <any other int> means failure when returned by a process. Furthermore, I continue to find it confusing that this is the opposite of the "natural" int equivalents for booleans, where false=0 and true=1 (or any other non-zero value). Perhaps this is not universal, but I find it logical to assume that the pairs (false, failure), and (true, success) should be correlated, rather than the reverse. Finally, why convolute the standard for the sake of newbies? By definition, they are people who need to learn more about the language .. and making mistakes (like returning 1) is the best way to do this. In fact, if there were going to be a change made, I would rather see them get rid of the fixed meaning of {return 0;} for success, and mandate {return EXIT_SUCCESS;} in its place. Just my 2 cent ... --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Falk Tannhäuser Guest Posted: Fri Apr 16, 2004 5:40 pm    Post subject: Re: return 1; suggestion Ioannis Vranos wrote: Quote: "James Kuyper" <kuyper (AT) wizard (DOT) net> wrote in message He finds "return 1;" to be easier to understand than "return EXIT_FAILURE;"? The second clearly implies that you're exiting the program, and that something failed. I have no idea what a newbie would conclude from "return 1", but it's rather unlikely to match what I just wrote. It is easier for a newbie to write return 1; rather than #include .. return EXIT_FAILURE; When you were newbie you were returning EXIT_FAILURE; in main() if you wanted to signal failure? I believe that one thing a newbie should learn is that, in many cases, it is preferable to have a program that is easy to /read/ than one that it is easy to /write/. 'EXIT_FAILURE' is clearly more descriptive about the programmer's intention than '1', even if it requires more keystrokes. Falk --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top llewelly Guest Posted: Sat Apr 17, 2004 5:36 pm    Post subject: Re: return 1; suggestion [email]ivr (AT) guesswh (DOT) at.emails.ru[/email] ("Ioannis Vranos") writes: Quote: Now it may sound a bit stuoid in the beginning. I was talking with someone who was using return 1; in main() to signal errors because #include return EXIT_FAILURE; is tiresome to write and also difficult for newbies to understand it. Wouldn't be better this to be added in the upcoming standard as a portable way ti signal error? Essentially return 1; to be equivalent to return EXIT_FAILURE; as return 0; is equivalent to return EXIT_SUCCESS; Do you realize that making 'return 1;' equivalent to 'return EXIT_FAILURE;' would make 'return true;' equivalent to 'return EXIT_FAILURE;' as well? --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Ioannis Vranos Guest Posted: Sat Apr 17, 2004 8:59 pm    Post subject: Re: return 1; suggestion "llewelly" <llewelly.at (AT) xmission (DOT) dot.com> wrote Quote: ivr (AT) guesswh (DOT) at.emails.ru ("Ioannis Vranos") writes: Do you realize that making 'return 1;' equivalent to 'return EXIT_FAILURE;' would make 'return true;' equivalent to 'return EXIT_FAILURE;' as well? While now returning true in main() is undefined behaviour. Ioannis Vranos --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top llewelly Guest Posted: Sun Apr 18, 2004 9:09 pm    Post subject: Re: return 1; suggestion [email]ivr (AT) guesswh (DOT) at.emails.ru[/email] ("Ioannis Vranos") writes: Quote: "llewelly" <llewelly.at (AT) xmission (DOT) dot.com> wrote in message news:86n05bcmbb.fsf (AT) Zorthluthik (DOT) local.bar... [email]ivr (AT) guesswh (DOT) at.emails.ru[/email] ("Ioannis Vranos") writes: Do you realize that making 'return 1;' equivalent to 'return EXIT_FAILURE;' would make 'return true;' equivalent to 'return EXIT_FAILURE;' as well? While now returning true in main() is undefined behaviour. [snip] I would like to see it become a required diagnostic. I'm chary of how much code that would break, however. And it doesn't seem terribly important. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Andrew Koenig Guest Posted: Mon Apr 19, 2004 4:08 pm    Post subject: Re: return 1; suggestion ""Ioannis Vranos"" <ivr (AT) guesswh (DOT) at.emails.ru> wrote Quote: Do you realize that making 'return 1;' equivalent to 'return EXIT_FAILURE;' would make 'return true;' equivalent to 'return EXIT_FAILURE;' as well? While now returning true in main() is undefined behaviour. Really? Why do you think so? --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Michiel Salters Guest Posted: Mon Apr 19, 2004 5:35 pm    Post subject: Re: return 1; suggestion [email]ivr (AT) guesswh (DOT) at.emails.ru[/email] ("Ioannis Vranos") wrote in message news:<c5s2i1$7ub$1 (AT) ulysses (DOT) noc.ntua.gr>... Quote: "llewelly" <llewelly.at (AT) xmission (DOT) dot.com> wrote in message news:86n05bcmbb.fsf (AT) Zorthluthik (DOT) local.bar... [email]ivr (AT) guesswh (DOT) at.emails.ru[/email] ("Ioannis Vranos") writes: Do you realize that making 'return 1;' equivalent to 'return EXIT_FAILURE;' would make 'return true;' equivalent to 'return EXIT_FAILURE;' as well? While now returning true in main() is undefined behaviour. No. true is converted to 1, which means main() returns 1. This is equivalent to exit(1). The meaning of exit(1) is implementation- defined per 18.3/8, and not undefined. Regards, Michiel Salters --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top llewelly Guest Posted: Mon Apr 19, 2004 5:37 pm    Post subject: Re: return 1; suggestion [email]ark (AT) acm (DOT) org[/email] ("Andrew Koenig") writes: Quote: ""Ioannis Vranos"" <ivr (AT) guesswh (DOT) at.emails.ru> wrote in message news:c5s2i1$7ub$1 (AT) ulysses (DOT) noc.ntua.gr... Do you realize that making 'return 1;' equivalent to 'return EXIT_FAILURE;' would make 'return true;' equivalent to 'return EXIT_FAILURE;' as well? While now returning true in main() is undefined behaviour. Really? Why do you think so? hm, the 3rd bullet of 18.3/8 says it is implementation-defined behaviour. I'd forgotten that. --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. 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