I'm porting a pretty old C (and a bit of C++) code basis from KEIL OS to Linux 32 bit.
When compiling with gcc/g++ 6.3 to 6.5 it works ok, when trying to do the same with gcc > 7.0 (tested with 7.3 and 8.2 on ubuntu 18.04) I get compilation errors:
/usr/include/bits/floatn-common.h:207:15: error: two or more data types in declaration specifiers
typedef float _Float32;
^~~~~~~~
/usr/include/bits/floatn-common.h:244:16: error: two or more data types in declaration specifiers
typedef double _Float64;
^~~~~~~~
/usr/include/bits/floatn-common.h:261:16: error: two or more data types in declaration specifiers
typedef double _Float32x;
^~~~~~~~~
/usr/include/bits/floatn-common.h:278:21: error: two or more data types in declaration specifiers
typedef long double _Float64x;
The compiler header (/usr/include/bits/floatn-common.h:261:16) file contains the following part:
# if __HAVE_FLOAT32
# if !__GNUC_PREREQ (7, 0) || defined __cplusplus
typedef float _Float32;
# endif
# if !__GNUC_PREREQ (7, 0)
# define __builtin_huge_valf32() (__builtin_huge_valf ())
# define __builtin_inff32() (__builtin_inff ())
# define __builtin_nanf32(x) (__builtin_nanf (x))
# define __builtin_nansf32(x) (__builtin_nansf (x))
# endif
# endif
Which tells me that this is only related to gcc > 7.0
most of the issues related to this error are missing ";" in structs or doing something like
void int myFunction(void){}
though I think this is not the case here because it appears in different compilation units and it works with previous versions of gcc/g++
using glibc version 2.27
My question: is there a way to disable this new compiler feature or eventually a hint from the community where to start searching