status of C++ support with GNULIB_NAMESPACE

[Bruno Haible]

Hi,

To see where we are on C++ GNULIB_NAMESPACE support, I ran
  $ ./gnulib-tool --create-testdir --with-c++-tests --with-tests 
--dir=/tmp/testdir
(takes one hour, be patient) and built it on a glibc system with
  $ ./configure CPPFLAGS="-DGNULIB_NAMESPACE=gggg -Wall" CC=g++
  $ make -k

Here are the findings:

* GNULIB_STRICT_CHECKING and GNULIB_NAMESPACE don't work together
  (errors for many functions). So, I removed the -DGNULIB_STRICT_CHECKING=1
  flag for this test.
  A possible fix would be to add a configure option --disable-strict-checking
  in the configure scripts of the testdirs.

* memrchr
./string.h:542:1: error: new declaration 'void* memrchr(const void*, int, 
size_t)'
/usr/include/string.h:117:28: error: ambiguates old declaration 'const void* 
memrchr(const void*, int, size_t)'

* savewd.h
  - use of INITIAL_STATE, ERROR_STATE, etc. without savewd:: qualifier
    (savewd.h:81, savewd.h:126).
  A possible fix would be to move the 'enum' definition out of 'struct savewd';
  this would be a no-op for C but not for C++.

* Many errors due to the fact that the .c files are meant to be compiled by a
  C compiler, not a C++ compiler, such that
  - 1065x "initializer-string for array of chars is too long"
  - 217x "invalid conversion from 'void*' to" some other pointer type
  - 59x "invalid conversion from 'const void*' to" some other pointer type
  - 53x other "invalid conversion from ... to ..."
  - 16x "declaration of ... has a different exception specifier"
    (due to 'throw ()')
  - use of identifier 'class' (dfa.c)
  - use of identifier 'new' (hash.c, glob.c)
  - use of gnulib functions without GNULIB_NAMESPACE:: qualifier (signbit,
    isfinite, globfree)
  - "new declaration ..." "ambiguates old declaration ..." (strcasestr,
    strerror_r, strstr)
  All these errors are in the category "Not a bug", IMO, because gdb and other
  packages can arrange to build the imported gnulib-lib/ directory using a
  C compiler rather than a C++ compiler.

Bruno