[gcc-15] ../.../blst.h: error: two or more data types in declaration specifiers

[SamWilsn]

Don't know if it's relevant, but this system used gcc 15.

# github.com/supranational/blst/bindings/go
In file included from ../go-mod/github.com/supranational/[email protected]/bindings/go/blst.go:18:
../go-mod/github.com/supranational/[email protected]/bindings/go/../blst.h:27:15: error: two or more data types in declaration specifiers
   27 | typedef _Bool bool; /* it's assumed that cgo calls modern enough compiler */
      |               ^~~~

blst/bindings/blst.h

Line 27 in 52cc60d

typedef _Bool bool; /* it's assumed that cgo calls modern enough compiler */

For a lot more detail, including build logs and system details, see: https://bugs.gentoo.org/943964

[dot-asm]

It appears that gcc>=14 fails if it's instructed with -std=c2x. Would it be correct assumption that gcc-15 (or your installation) defaults to [non-finalized] c2x? Even newer clang complains about C++ type redeclaration. WTF? It's a C++ type, and we're compiling C! Neither seems to be fair :-) But that's life... I'll look into it, meanwhile you have to find a way to instruct your compiler to stick to -std=<less-than-c2x>...

[SamWilsn]

I'm using it through your go bindings (specifically as a dependency of geth.) Can I pass cflags through there?

[dot-asm]

Can I pass cflags through there?

CGO_CFLAGS environment variable controls the C compiler flags in cgo context, but one has to recognize that it's "non-cumulative," i.e. if you set it, you have to set all the relevant flags, most notably -O2. See go env CGO_CFLAGS for your defaults. At the same time you have to keep in mind that if you rely on some build script and it sets the variable in question, it will simply override yours.

[SamWilsn]

Looks like C23 is actually finished as of Oct. 31, and GCC defaults to it now. bool is a real C type 🎉

[dot-asm]

Well, it's still not fair :-) The standard says the new __STDC_VERSION__ is 202311L, so one shouldn't expect things to break with __STDC_VERSION__ 202000L, which is the value set by gcc<=14 -std=c2x. Yet it's only gcc>=14 that fails. What does your compiler set? In other words what does gcc -dM -E -x c /dev/null | grep __STDC_VERSION__ print?

[SamWilsn]

gentoo-chroot ~ # gcc-15 -dM -E -x c /dev/null | grep __STDC_VERSION__
#define __STDC_VERSION__ 202311L

[dot-asm]

I'm not sure that they will keep C23 as default in the final release, but the report was very useful anyway. Thanks!

[SamWilsn]

Thanks a ton! Do you happen to know roughly when this'll make it into a release?