Menu
I tried to compile the code below with Clang
class Prasoon{
static const int dummy = 0;
};
int const Prasoon::dummy = 0;
int main(){}
The above code did not give any error when compiled with Clang.
prasoon@prasoon-desktop ~ $ clang++ --version
clang version 2.8 (trunk 107611)
Target: i386-pc-linux-gnu
Thread model: posix
prasoon@prasoon-desktop ~ $ cat bug.cpp
class Prasoon{
private:
static const int dummy = 0;
};
int const Prasoon::dummy = 0;
int main(){}
prasoon@prasoon-desktop ~ $ clang++ bug.cpp
prasoon@prasoon-desktop ~ $
But when I compiled the same code with g++ I got an error as expected.
prasoon@prasoon-desktop ~ $ g++ bug.cpp
bug.cpp:8: error: duplicate initialization of ‘Prasoon::dummy’
So have I found a bug in Clang?
241
Clang is also provided in all major BSD or GNU/Linux distributions as part of their respective packaging systems. From Xcode 4.2, Clang is the default compiler for Mac OS X.
Clang operates in tandem with the LLVM compiler back end and has been a subproject of LLVM 2.6 and later. As with LLVM, it is free and open-source software under the Apache License 2.0 software license. Its contributors include Apple, Microsoft, Google, ARM, Sony, Intel, and AMD.
Sometimes a program is a lot faster when compiled with GCC, sometimes it's a lot faster with clang. Usually it's marginally faster with GCC. Clang attempts to unroll loops really, really aggressively. Even at -O2 : Clang's loop unrolling attempts at -O2 are more aggressive than GCC's loop unrolling attempts at -O3 .
Clang is much faster and uses far less memory than GCC. Clang aims to provide extremely clear and concise diagnostics (error and warning messages), and includes support for expressive diagnostics. GCC's warnings are sometimes acceptable, but are often confusing and it does not support expressive diagnostics.
Yes, you have found a bug.
The rule is expressed in the standard:
9.4.2-3: If a static data member is of const literal type, its declaration in the class definition can specify a brace-or- equal-initializer in which every initializer-clause that is an assignment-expression is a constant expression. A static data member of literal type can be declared in the class definition with the constexpr specifier; if so, its declaration shall specify a brace-or-equal-initializer in which every initializer-clause that is an assignment-expression is a constant expression. [ Note: In both these cases, the member may appear in constant expressions. — end note ] The member shall still be defined in a namespace scope if it is used in the program and the namespace scope definition shall not contain an initializer.
166
Yes this is indeed a bug. I stumbled upon your bug report to clang -- thanks for taking the time to submit it :) While this bug was initially logged as a bug on 4/23/10, your submission brought it to my attention and I have submitted a simple patch to the developer's group for their review.
26
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
