A glimpse of undefined behavior in C
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A glimpse of undefined behavior in C
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Re: A glimpse of undefined behavior in C
#2Not "well-defined" is the proper terminology.
Re: A glimpse of undefined behavior in C
#3Sequence points are an interesting topic on their own.
Re: A glimpse of undefined behavior in C
#4The way I learned that in C a long time ago was "post increment" was "post statement increment".
Re: A glimpse of undefined behavior in C
#5Not "well-defined" is the proper terminology.
What is the difference? I do not see "well-defined" in the "Terms, definitions, and symbols" part of the standard.
Re: A glimpse of undefined behavior in C
#6The way I learned that in C a long time ago was "post increment" was "post statement increment".
exactly. This is precisely to spec; and I got the answer of 60 immediately on looking at the code.
Re: A glimpse of undefined behavior in C
#7Knowing how exactly sequence points work might be an advanced topic, but I am not sure I'd hire a junior C/C++ programmer if he has not heard of sequence points. If somebody has, then he clearly won't do something like this code. I am not 100% sure in how they work either (haven't programmed C for 4 years), so I just avoid these kind of unnecessary complications in the code, if not for myself, then for the guy who comes after me, and who, if he has a bad day, may inadvertently cause some trouble.
Really, that's one of the reason why Java still works well at big companies. The code is usually so verbose and 'un-smart' that it's quite hard for programmers with minority complex to obfuscate it when they're trying to prove that they're smart. It's a shame however that if the language is primitive then you can always create a big framework to obfuscate stuff. :)
Re: A glimpse of undefined behavior in C
#8The way I learned that in C a long time ago was "post increment" was "post statement increment".
exactly. This is precisely to spec; and I got the answer of 60 immediately on looking at the code.
This is incorrect; it is undefined behavior according to the spec: http://www.reddit.com/r/programming/comments/1rrefp/a_glimps...
Re: A glimpse of undefined behavior in C
#9Earlier quoted context omitted.
exactly. This is precisely to spec; and I got the answer of 60 immediately on looking at the code.
This is incorrect; it is undefined behavior according to the spec: http://www.reddit.com/r/programming/comments/1rrefp/a_glimps...
Ok, so do any other compilers handle it differently?
Re: A glimpse of undefined behavior in C
#10I just ran this after compiling it with clang-500.2.79 based on LLVM 3.3svn, and the output was 140. Maybe GCC is to blame?