Boost Users :
Dave Steffen wrote:
Gen Zhang writes:
> I believe The Book specifically allows an optional semicolon at the end
> of a function declaration in the global scope. They are illegal in a
> class. And necessary at the end of a class/struct definition. I have a
> friend who runs into this problem a lot. :D
Yeah, this is one question - is it legal?
According to the grammar listed as Appendix A of "The C++ Programming Language,
Special Edition", by Stroustrup...
A translation-unit, often called a source file, is
a sequence of declarations:
So 0 or more declaration-seq makes up a source file.
p. 803 (bottom of page) lists the production rule for a declaration-seq:
p. 804 (top of page) tells us the production rule for a declaration rule.
a declaration may be entirely replaced by a block-declaration.
The next production rule tells us that a block-declaration may be entirely
replaced by a simple-declaration.
The next production rule is:
Note that the only thing that isn't optional is the semicolon.
Presuming the book has no typos, presuming the grammar is a valid representation
of the C++ specification, then it would seem that a spurious semicolon at
the end of any global declaration is itself a global declaration and is not
an error. I find it distasteful, but having the extra semicolon does
seem to be valid - if my presumptions are accurate.
And while GCC's acceptance doesn't mean it's valid C++... attached is the
// Compiled (gcc 3.4.3) and run on a Red Hat system (2.4.20-8 kernel) with:
// g++ -o feh feh.C && ./feh
/* Next line is sole output.
int main(int argc, char **argv)
std::cerr << "feh!\n";
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