Re: gcc 4.3pre (20070824) vs. gmp.h: error: ‘std::FILE’ has not been declared

[Patrick Pelissier]

Hello,

  I have heard that g++ 4.3 has reduced a lot the dependencies between
the system headers.
  Before FILE was defined even if stdio.h was not included explicitly
(See the output of g++ -E).
 Now (4.3), it is not more defined, thought the error.

 I think the correct way to fix is:

#if defined (__cplusplus)
extern "C" {
#ifdef _GMP_H_HAVE_FILE
using std::FILE;
#endif
#endif

 But I am not a C++ expert.

  For checking of givaro inside the configure, as a work-around,
  I suggest including cstdio explicitly before gmp.h.

--
 Sincerely,
  Patrick Pélissier

On 8/26/07, Michael Abshoff
<Michael.Abshoff at fsmath.mathematik.uni-dortmund.de> wrote:
> Hello,
>
> I ran into the following problem when compiling the following AC_CHECK
> snippet with gcc 4.3pre (20070824 snapshot) when using gmp release 4.2.1:
>
> [mabshoff at m940 src]$ cat gmp-version-check.c
> #include <gmp.h>
>
> int main ()
> {
>   if (__GNU_MP_VERSION < 4)
>     return -1;
>   else
>     return 0;
> }
>
> [mabshoff at m940 src]# g++ -I ../../../../local/include/ gmp-version-check.c
> -lgmp
> In file included from gmp-version-check.c:1:
> ../../../../local/include/gmp.h:515: error: 'std::FILE' has not been declared
>
> (the code compiled fine with gcc, because the offending bit is ifdefd with
> __cplusplus). Removing the offending "using std::FILE" make the code in
> question (which originated in the AC_CHECK of givaro) and givaro itself (a
> C++ library for arithmetic and algebraic computations) compile. But the
> sample problem should show up in any C++ libary or code including gmp.h
>
> Now my questions:
>
> - Is that the recommended work-around or am I doing something wrong?
> - I have to admit my ignorance: Why are we using "using std::FILE" there?
> Is it even needed for g++?
>
> Cheers,
>
> Michael
>
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