Re: Configure check for static_cast is broken

[Dmitri Gribenko]

On Wed, Apr 10, 2013 at 6:46 PM, Dmitri Gribenko <address@hidden> wrote:
> Dear ncurses maintainers,
>
> Configure fails to detect that clang 3.2 fully supports a c++98
> feature -- static_cast because the code that it uses to check this is
> not valid c++.

Unfortunately, this is not all.  Similarly, check for size of bool is broken:

configure:18808: checking for size of bool
configure:18861: clang++ -o conftest -fPIC -O2 -march=native
-I/opt/eb/software/OpenBLAS/0.2.6-cgompi-1.1.6-LAPACK-3.4.2/include
-I/opt/eb/software/ScaLAPACK/2.0.2-cgompi-1.1.6-OpenBLAS-0.2.6-LAPACK-3.4.2/include
-I/opt/eb/software/FFTW/3.3.3-cgompi-1.1.6/include -D_GNU_SOURCE
-DNDEBUG  -L/opt/eb/software/GCC/4.7.2/lib64
-L/opt/eb/software/OpenBLAS/0.2.6-cgompi-1.1.6-LAPACK-3.4.2/lib
-L/opt/eb/software/ScaLAPACK/2.0.2-cgompi-1.1.6-OpenBLAS-0.2.6-LAPACK-3.4.2/lib
-L/opt/eb/software/FFTW/3.3.3-cgompi-1.1.6/lib conftest.cc  -lm
-lpthread >&5
configure:18842:1: error: C++ requires a type specifier for all declarations
main()
^~~~
1 error generated.
configure:18864: $? = 1
configure: program exited with status 1
configure: failed program was:
#line 18819 "configure"
#include "confdefs.h"

#include <stdlib.h>
#include <stdio.h>

#if defined(__cplusplus)

#ifdef HAVE_GXX_BUILTIN_H
#include <g++/builtin.h>
#elif HAVE_GPP_BUILTIN_H
#include <gpp/builtin.h>
#elif HAVE_BUILTIN_H
#include <builtin.h>
#endif

#else

#if 1
#include <stdbool.h>
#endif

#endif

main()
{
        FILE *fp = fopen("cf_test.out", "w");
        if (fp != 0) {
                bool x = true;
                if ((bool)(-x) >= 0)
                        fputs("unsigned ", fp);
                if (sizeof(x) == sizeof(int))       fputs("int",  fp);
                else if (sizeof(x) == sizeof(char)) fputs("char", fp);
                else if (sizeof(x) == sizeof(short))fputs("short",fp);
                else if (sizeof(x) == sizeof(long)) fputs("long", fp);
                fclose(fp);
        }
        return(0);
}

configure:18887: result: unknown
configure:18893: WARNING: Assuming unsigned for type of bool

To resolve this, just declare main as 'int main()'.

Dmitri

--
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <address@hidden>*/