On 2013-07-20 18:25, David Blaikie wrote:
On Sat, Jul 20, 2013 at 10:01 AM, Sian Mountbatten
<[email protected]> wrote:
On 2013-07-20 17:44, David Blaikie wrote:

Nothing obviously wrong with that - yes, jumping in with a debugger
might be an option, but the code looks simple enough that I'd wonder
if it's an issue with linking or the standard library.

On Sat, Jul 20, 2013 at 6:46 AM, Sian Mountbatten
<[email protected]> wrote:

Dear List

If I compile the file main.cpp to regex using this command:
    clang++ -g -std=c++11 -stdlib=libc++ -o regex main.cpp
I get no warnings, no errors, in fact no console output from clang++.
When the program is run, it produces "\w+\d*" on the console.

Now, if I compile with this command:
   clang++ -g -std=c++11 -o main.o -c main.cpp
and then link with this command:
   clang++ -g -stdlib=libc++ -o regex main.o
again, I get no output from clang++. Unfortunately, when the output
program is run, it fails with "Segmentation violation".

Again, I'm assuming you've invoked UB & the two different standard
libraries are just failing in different ways. Once we see the code,
that might change.

What does "UB" mean?
Undefined Behavior ( a good read on the subject if Chris Lattner's 3
part series: 
http://blog.llvm.org/2011/05/what-every-c-programmer-should-know.html
) - though from your example there's nothing obviously wrong that I
can see.


The code was lifted from Bjarne's book, so I'd be surprised if there *was* anything wrong with it. Because I succeeded in compiling LLVM/Clang using the GNU C++ library, I am now trying to build LLVM/Clang (svn rev. 186765) using the already compiled Clang++ and libc++. We shall
see if that succeeds.

--
Sian Mountbatten <www.poenikatu.co.uk>
Learning C++!!!
I'm an FSF member (10888)
Help us support software freedom! http://www.fsf.org/jf?referrer=10888


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