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Day: GNOME OSDay: GNOME OSPosted Aug 10, 2012 10:57 UTC (Fri) by jwakely (subscriber, #60262)In reply to: Day: GNOME OS by mathstuf Parent article: Day: GNOME OS If C++ hadn't supported C casts (or had used a FFI for C interop, as you suggested above) it would never have achieved the success it enjoys today, which only happened by building on C's popularity and success. C compatibility is sometimes a millstone around the neck of C++ now, but without it this discussion probably wouldn't even be happening. Without supporting C-style casts you couldn't write something as simple as this and have it be valid in both C and C++: int* p = (int*)malloc(n*sizeof(int));It's the right design for a C-style cast to invoke a user-defined conversion if one exists, for the reasons nix gives. Why would you want to use C-style casts in templates anyway? Code in templates doesn't need to be C-compatible. You can't cast between arbitrary POD types anyway, in C or C++. Can you give an example that shows what you mean?
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Day: GNOME OS Posted Aug 10, 2012 11:09 UTC (Fri) by hummassa (subscriber, #307) [Link]
You can't c-cast from a POD type to another, but you can c-cast from a pointer-to-any-type to another (even if you have to cast to void* in the middle).
Day: GNOME OS Posted Aug 10, 2012 11:18 UTC (Fri) by jwakely (subscriber, #60262) [Link]
Was mathstuf's statement "it acts differently based on whether the template type is POD or not" talking about casting pointers?
Day: GNOME OS Posted Aug 10, 2012 14:59 UTC (Fri) by Cyberax (✭ supporter ✭, #52523) [Link]
You can always do:
>int *p = reinterpret_cast<int*>(malloc(n*sizeof(int))
Day: GNOME OS Posted Aug 10, 2012 15:51 UTC (Fri) by jwakely (subscriber, #60262) [Link]
How would that be valid C?
Day: GNOME OS Posted Aug 10, 2012 16:54 UTC (Fri) by Cyberax (✭ supporter ✭, #52523) [Link]
It's not, and that's the point. C++ could have avoided lots of warts caused by C-compatibility without losing in functionality.
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