lin li <helloworld_lilin@xxxxxxxxx> writes: > I have some questions about GCC/G++ 4.4.1. The first questions is > that we find that the gcc compiler support some C99 extensions by > default. For example, the gcc 4.4 document says "New character data > types, per TR 19769: New character types in C, are now supported for > the C compiler in -std=gnu99 mode, as __CHAR16_TYPE__ and > __CHAR32_TYPE__". However, the new __CHAR16_TYPE__ and > __CHAR32_TYPE__ are recognized by the compiler by default. And it > seems the -ansi and other -std options do not work. Do you aware > this bug? > > Another thing is that I am reading the document about porting to gcc 4.4 here: > http://gcc.gnu.org/gcc-4.4/porting_to.html > > I am interested in the 'Header dependency changes' section. It means > our legacy codes need to be change for this. Could you tell me why > you made this change? Please do not send e-mail to both gcc@xxxxxxxxxxx and gcc-help@xxxxxxxxxxxx This message is appropriate for gcc-help. Please take any followups there. Thanks. Names that begin with a double underscore, like __CHAR16_TYPE__, are reserved for use by the compiler. In c90 mode we try to be careful to compile any program which conforms to the ISO C90 standard. Such a program can not use a name like __CHAR16_TYPE__. So it's not clear to me that defining these types in c90 mode is a bug. I wouldn't personally be opposed to changing it, but I would want to see a reason to make the change. The fact that the C90 standard does not define __CHAR16_TYPE__ is not, as far as I can see, a reason that gcc should not define it in c90 mode. I believe that the header dependency changes were made to speed up C++ compilations. Ian
