Issue #20908 has been updated by hansdegraaff (Hans de Graaff). We initially opened this bug because we had multiple cases of this issue and the one in brotli was an example. Another case shows up in io-console: ``` x86_64-pc-linux-gnu-gcc -I. -I/usr/include/ruby-3.1.0/x86_64-linux -I/usr/include/ruby-3.1.0/ruby/backward -I/usr/include/ruby-3.1.0 -I. -DHAVE_RB_IO_DESCRIPTOR -DHAVE_RB_IO_GET_WRITE_IO -DHAVE_TERMIOS_H -DHAVE_CFMAKERAW -DHAVE_SYS_IOCTL_H -DHAVE_RB_IO_WAIT=1 -fPIC -std=gnu23 -o console.o -c console.c In file included from /usr/include/ruby-3.1.0/ruby/ruby.h:26, from /usr/include/ruby-3.1.0/ruby.h:38, from console.c:9: console.c: In function ‘InitVM_console’: /usr/include/ruby-3.1.0/ruby/internal/anyargs.h:287:135: error: passing argument 3 of ‘rb_define_method_m3’ from incompatible pointer type [-Wincompatible-pointer-types] 287 | #define rb_define_method(klass, mid, func, arity) RBIMPL_ANYARGS_DISPATCH_rb_define_method((arity), (func))((klass), (mid), (func), (arity)) | ^~~~~~ | | | __attribute__((noreturn)) VALUE (*)(int, const VALUE *, VALUE, VALUE) {aka __attribute__((noreturn)) long unsigned int (*)(int, const long unsigned int *, long unsigned int, long unsigned int)} console.c:1815:5: note: in expansion of macro ‘rb_define_method’ 1815 | rb_define_method(rb_cIO, "pressed?", console_key_pressed_p, 1); | ^~~~~~~~~~~~~~~~ ``` `console_key_pressed_p` is defined as `rb_f_notimplement` and `RUBY_METHOD_FUNC` is not used anywhere in this gem. ---------------------------------------- Bug #20908: Ruby extension builds fail with GCC 15 which defaults to -std=gnu23 https://bugs.ruby-lang.org/issues/20908#change-110817 * Author: thesamesam (Sam James) * Status: Third Party's Issue * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Hi! Upcoming GCC 15 defaults to C23 (`-std=gnu23`). One thing C23 changes is removing unprototyped functions, so `void foo()` now means `void foo(void)`, rather than "any arguments". Ruby extensions fail to build as a result with GCC 15. This was reported downstream in Gentoo at https://bugs.gentoo.org/943784 where brotli-0.6.0 is an example: ``` make: Entering directory '/var/tmp/portage/dev-ruby/brotli-0.6.0/work/ruby32/brotli-0.6.0/ext/brotli' x86_64-pc-linux-gnu-gcc -I. -I/usr/include/ruby-3.2.0/x86_64-linux -I/usr/include/ruby-3.2.0/ruby/backward -I/usr/include/ruby-3.2.0 -I. -DHAVE_BROTLI_DECODE_H -DHAVE_BROTLI_ENCODE_H -fPIC -O2 -pipe -march=native -fno-diagnostics-color -o brotli.o -c brotli.c In file included from /usr/include/ruby-3.2.0/ruby/ruby.h:27, from /usr/include/ruby-3.2.0/ruby.h:38, from brotli.h:4, from brotli.c:1: brotli.c: In function ‘Init_brotli’: /usr/include/ruby-3.2.0/ruby/internal/anyargs.h:363:45: error: passing argument 3 of ‘rb_define_singleton_method_m1’ from incompatible pointer type [-Wincompatible-pointer-types] 363 | # define RUBY_METHOD_FUNC(func) RBIMPL_CAST((VALUE (*)(ANYARGS))(func)) | ^ | | | VALUE (*)(void) {aka long unsigned int (*)(void)} /usr/include/ruby-3.2.0/ruby/internal/anyargs.h:308:144: note: in definition of macro ‘rb_define_singleton_method’ 308 | #define rb_define_singleton_method(obj, mid, func, arity) RBIMPL_ANYARGS_DISPATCH_rb_define_singleton_method((arity), (func))((obj), (mid), (func), (arity)) | ^~~~ /usr/include/ruby-3.2.0/ruby/internal/anyargs.h:363:33: note: in expansion of macro ‘RBIMPL_CAST’ 363 | # define RUBY_METHOD_FUNC(func) RBIMPL_CAST((VALUE (*)(ANYARGS))(func)) | ^~~~~~~~~~~ brotli.c:478:55: note: in expansion of macro ‘RUBY_METHOD_FUNC’ 478 | rb_define_singleton_method(rb_mBrotli, "deflate", RUBY_METHOD_FUNC(brotli_deflate), -1); | ^~~~~~~~~~~~~~~~ /usr/include/ruby-3.2.0/ruby/internal/anyargs.h:271:21: note: expected ‘VALUE (*)(int, union <anonymous>, VALUE)’ {aka ‘long unsigned int (*)(int, union <anonymous>, long unsigned int)’} but argument is of type ‘VALUE (*)(void)’ {aka ‘long unsigned int (*)(void)’} 271 | RBIMPL_ANYARGS_DECL(rb_define_singleton_method, VALUE, const char *) | ^~~~~~~~~~~~~~~~~~~~~~~~~~ /usr/include/ruby-3.2.0/ruby/internal/anyargs.h:254:41: note: in definition of macro ‘RBIMPL_ANYARGS_DECL’ 254 | RBIMPL_ANYARGS_ATTRSET(sym) static void sym ## _m1(__VA_ARGS__, VALUE(*)(int, union { VALUE *x; const VALUE *y; } __attribute__((__transparent_union__)), VALUE), int); \ | ^~~ ``` The `ANYARGS` macro can't work in its current form, as defined at e.g. https://github.com/ruby/ruby/blob/f127bcb8294fd417c253dd7acab3ff3b9f0bf555/p...: ``` #ifndef ANYARGS # ifdef __cplusplus # define ANYARGS ... # else # define ANYARGS # endif #endif ``` ... because of the change in C23 I mentioned above, i.e. `(ANYARGS)` being `()` now means no arguments, not any. I note that Ruby was adapted in part already for this change, see e.g. https://github.com/ruby/ruby/commit/4e64edb6cd8d1b444c591bfd50ec3d357e794f6e, but it appears that the headers that extensions need to build against aren't yet ready. -- https://bugs.ruby-lang.org/