On Tue, Feb 3, 2015 at 2:01 PM, Niall Douglas
On 3 Feb 2015 at 22:02, Stephen Kelly wrote:
I confess that I haven't seen this in any way related to C++17. I would certainly be skeptical of anyone spending any time on something as speculative as a future C++ standard before it's finalized.
That's no reason not to educate yourself on it, and it's no reason not to try the clang implementation.
For the record, you can simulate clang's modules using any compiler by simply compiling in everything as a single translation unit. A simple shell script can create a file which includes all the source files at once.
If it works as a single translation unit, it'll work under clang modules. If it doesn't, well then you've got some ODR violation going on (very common in source files which assume they own their translation unit) and it may or may not work under clang modules depending.
Wait, I'm confused... is this actually true? Maybe I'm missing something, but I can imagine a simple example of an anonymous namespace in two translation units that define similar functions (i.e. each would have been defined and used in their own cpp in the multi-translation-unit version). This is not an ODR violation but it would fail compilation if done as you suggest. I'm not very familiar with modules as they are currently, but it seems like the assertion must be erroneous. -- -Matt Calabrese