sys-socket.in.h/alignof.h usage problem with C++

[Gary V. Vaughan]

While trying to compile a C++ package, and using the gnulib socket modules to 
paper over the differences between various vendor implementations, I tripped 
over the following error on Solaris 2.6 and 7:

"lib/alignof.h", line 28: Error: Template declarations cannot have extern "C" 
linkage.
1 Error(s) detected.

Triggered by the following code in alignof.h:

/* Determine the alignment of a structure slot (field) of a given type,
   at compile time.  Note that the result depends on the ABI.
   Note: The result cannot be used as a value for an 'enum' constant,
   due to bugs in HP-UX 10.20 cc and AIX 3.2.5 xlc.  */
#if defined __cplusplus
  template <class type> struct alignof_helper { char __slot1; type __slot2; };
...

The problem is that the package C++ headers wrap inclusions of C headers in 
`extern "C"', which seems like a reasonable thing to do.

I'm curious who is wrong here: Is it wrong for gnulib's alignof.h to use C++ 
conditionally and assume that it is not included from inside an `extern "C"' in 
an outer file?  Is it wrong for the package to mistrust the system C headers so 
much that they are only included to a C++ file inside an `extern "C"' 
declaration?  Or is it wrong for the C++ compiler to complain about use of 
templates inside `extern "C"'?

I have a workaround already (moving `#include <sys/socket.h>' outside the 
`extern "C"'), but I'm curious about the real culprit, and maybe the gnulib 
generated headers want to work properly when used like this?

Cheers,
-- 
Gary V. Vaughan (address@hidden)

PGP.sig
Description: This is a digitally signed message part