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[Bug libc/11157] __block is a reserved word with clang -fblocks


------- Additional Comments From bonzini at gnu dot org  2010-06-08 07:39 -------
> By convention, double underscores are reserved for the compiler, single
underscores for the libc.

This is wrong and makes no sense.  By _the standard_ double underscores are
reserved for the implementation (and the namespace is shared by the compiler and
libc; they have to live together).  There are no conventions about how to share
the namespace.

> Using them as parameter names in the header is entirely wrong and is not
guaranteed to work on any standards-compliant compiler.

This is also imprecise.  It is not guaranteed to work, period.  Your
interpretation of the standard is that libc should not use argument names in its
header file prototypes.  I kind of agree that it is safer and it would fix _this
particular case_ but in general it is not possible.  It would mean no inlines
and in C++ not even templates, unless you want to "uglify" foo as __libc_foo
which is not reasonable.

GCC has a "fixincludes" utilities that adapts problematic headers.  Most of the
time it fixes code that is indeed wrong according to the standard, but a few
adjustments are for conflicts with its own usage of __ identifiers.  If clang
doesn't have a fixincludes utility, that's its problem.

BTW the workaround is simply to do

   #define __block __glibc_block
   #include <unistd.h>
   #undef __block

which is all but unreasonable.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|                            |INVALID


http://sourceware.org/bugzilla/show_bug.cgi?id=11157

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