Ulrich Eckhardt <[EMAIL PROTECTED]> writes: > Summary of problems: > A) In some inlined functions, pointers where cast to void* before being > assigned to a somestruct*. I wonder why the cast to void*? I admit that I > didn't check what exact type they where before, but doesn't it work just the > same and is clearer to directly cast them to somestruct* ? > C++ refuses implicit type-conversions that are not safe and this doesn't > compile therefore.
The C++ meaning of 'void' and the C meaning of 'void' are not compatible with each other. I'm not sure exactly which casts you are talking about here; I might be able to comment if you could give a more specific citation. > B) There was one case (in cthreads.h) where 'catch' was used as identifier, > additionally, there where quite some cases where 'class' was used (in > ports.h). Right--legal C identifiers > C) While not important for using the headers, I found local > functions in some C-files. In fact I first triple-checked that that > was really the case, because I thought that local functions where > forbidden in C as in C++. Can someone clarify me if that is rather > new and standard C? It's a new feature in GCC that is extensively used in Hurd and Hurd-related libc code. > D) trivfs uses some hook-function-pointers that the user can set to > their own functions. I have been trying for an hour or so to get the > right syntax for one of those but failed. I still don't understand > the error-messages g++ gave me if necessary, I will provide more > facts later, I don't have the GNU/Hurd grazing on my LAN currently. Can you give a specific example? I can't help you with what C++ syntax is supposed to match, but I can certainly explain the C declarations. I certainly would not assume that C++ has not changed the meaning of some more complicated function declarators too. > E) There where some casts from int to an enumeration. Again, C++ requires > those to be done explicitly. Not a bug in C. > To be honest, I underestimated the amount of changes it takes to > postincrement the C-headers. Maybe the proposal from Kimmo K. I. Surakka > might be a better start. However, as he already said, this doesn't solve > implicit conversions of void* or enum. > Pondering over that, I just started to wonder if one couldn't #pragma the > compiler to do what one wants, any gcc-expert here ? Ah, well, a useful feature might be a syntax for C++ that said "the following code is C code, not C++ code" and did the right thing pervasively. But that feature does not exist. I think you can now see why merely removing "class" from ports.h and "catch" from cthreads.h is not the only change you'd be requesting. Making the headers work with C++ might even be a pervasive and ongoing maintenance hassle. Thomas
