Re: Build issues with libgnu

[Johannes Zarl]

I've taken a look into the standard, and indeed it seems that gcc is too 
lenient in this case and should actually reject the code like icpc does.

I've opened a bug report on this:
https://savannah.gnu.org/bugs/index.php?43171

Cheers,
  Johannes

On Monday, 8. September 2014, 15:45:19, Johannes Zarl wrote:
> Hi again,
> 
> I think I've isolated the issue I'm having now. When I try to compile
> Octave using Intel compilers, I get errors like this:
> 
> ../../libgnu/stdio.h(948): error: declaration is incompatible with previous
> "getchar" (declared at line 522 of "/usr/include/stdio.h")
>   _GL_CXXALIAS_SYS (getchar, int, (void));
> 
> The problem seems to be rooted in the file liboctave/cruft/misc/f77-fcn.h,
> which includes libgnu/stdio.h. The following code triggers the error:
> 
> extern "C" {
> #include <stdio.h>
> }
> 
> Given that libgnu/stdio.h already declares getchar and other functions as
> "extern C", what is wrapping the #include (and therefore the namespace
> blocks inside it) in an extern C region supposed to achieve?
> 
> Is icpc incorrect in throwing an error here?
> 
> Thanks,
>   Johannes
> 
> 
> 
> P.S.: Here is a short demonstration of the issue without libgnu:
> 
> # cat > test.cpp <<EOF
> extern "C" {
> #include <stdio.h>
> namespace GNULIB_NAMESPACE
> {
>     static int (*getchar) (void) = ::getchar;
> }
> }
> EOF
> # g++ -o test.o -c test.cpp
> -> no error here
> # icpc -o test.o -c test.cpp
> test.cpp(5): error: declaration is incompatible with previous "getchar"
> (declared at line 522 of "/usr/include/stdio.h")
>       static int (*getchar) (void) = ::getchar;
>                    ^
> 
> compilation aborted for test.cpp (code 2)
> 
> 
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