Comment by o11c
2 days ago
> the lack of standardization for name-mangling, or even a way mangle or de-mangle names at compile-time.
Like many things, this isn't a C++ problem. There is a standard and almost every target uses it ... and then there's what Microsoft does. Only if you have to deal with the latter is there a problem.
Now, standards do evolve, and this does give room for different system libraries/tools to have a different view of what is acceptable/correct (I still have nightmares of trying to work through `I...E` vs `J...E` errors) ... but all the functionality does exist and work well if you aren't on the bleeding edge (fortunately, C++11 provided the bits that are truly essential; everything since has been merely nice-to-have).
Like many things people claim "isn't a C++ problem but an implementation problem"... This is a C++ problem. Anything that's not nailed down by the standard should be expected to vary between implementations.
The fact that the standard doesn't specify a name mangling scheme leads to the completely predictable result that different implementations use different name mangling schemes.
The fact that the standard doesn't specify a mechanism to mangle and demangle names (be it at runtime or at compile time) leads to the completely predictable result that different implementations provide different mechanisms to mangle and demangle names, and that some implementations don't provide such a mechanism.
These issues could, and should, have been fixed in the only place they can be fixed -- the standard. ISO is the mechanism through which different implementation vendors collaborate and find common solutions to problems.
> The fact that the standard doesn't specify a name mangling scheme leads to the completely predictable result that different implementations use different name mangling schemes.
The ABI mess predates the standard by years and if we look that far back the Annotated C++ Reference Manual included a scheme in its description of the language. Many compiler writers back then made the intentional choice to ignore it. The modern day ISO standard would not fare any better at pushing that onto unwilling compiler writers than it fared with the c++03 export feature.
Well yeah, it can't be fixed now. It could have been specified near the beginning of the life of the language though, and the standard would've been the right place to do that.
I'm saying that the non-standard name mangling is a problem with C++. I'm not saying that it's an easily solvable problem.
> Anything that's not nailed down by the standard should be expected to vary between implementations.
When you have one implementations you have a standard. When you have two implementations and a standard you don’t actually have a standard in practice. You just have two implementations that kind of work similarly in most cases.
While the major compilers do a fantastic job they still frequently disagree about even “well defined” behavior because the standard was interpreted differently or different decisions were made.
> When you have two implementations and a standard you don’t actually have a standard in practice
This simply isn't true. Plenty of standardized things are interchangeable, from internet RFCs followed by zillions of players and implementations of various RFCs, medical device standards, encryption standards, weights and measures, currency codes, country codes, time zones, date and time formats, tons of file formats, compression standards, the ISO 9000 series, ASCII, testing standards, and on and on.
The poster above you is absolutely correct - if something is not in the standard, it can vary.
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If you have an area where the standard is ambiguous about its requirements, then you have a bug in the standard. And hopefully you also have a report to send along to help it communicate itself more clearly.
This is like getting mad at ISO 8601 because it doesn't define the metric system.
No standard stands alone in its own universe; complementary standards must necessarily always exist.
Besides, even if the C++ standard suddenly did incorporate ABI standards by reference, Microsoft would just refuse to follow them, and nothing would actually be improved.
A better situation than today would be only having to deal with Microsoft and Not Microsoft, rather than multiple different ways of handling the problem that can differ unexpectedly
> There is a standard and almost every target uses it ... and then there's what Microsoft does. Only if you have to deal with the latter is there a problem.
Sounds like there isn't a standard, then.
It's Itanium and MSVC. That's it, that's the list.