Ruby

Compiling gem with C++ extension fails on alpine 3xx with Ruby 3.0.0 and Ruby 3.0.1
(does not fail on Ubuntu 18 ¯\(ツ)/¯)

Error:

compiling testgem.cc In file included from /root/.rbenv/versions/3.0.0/include/ruby-3.0.0/ruby/ruby.h:39, from /root/.rbenv/versions/3.0.0/include/ruby-3.0.0/ruby.h:38, from testgem.cc:2: /root/.rbenv/versions/3.0.0/include/ruby-3.0.0/ruby/internal/memory.h:275:16: error: conflicting declaration of 'void* ruby_nonempty_memcpy(void*, const void*, size_t)' with 'C' linkage 275 | #define memcpy ruby_nonempty_memcpy | ^~~~~~~~~~~~~~~~~~~~ /root/.rbenv/versions/3.0.0/include/ruby-3.0.0/ruby/internal/memory.h:265:1: note: previous declaration with 'C++' linkage 265 | ruby_nonempty_memcpy(void *dest, const void *src, size_t n) | ^~~~~~~~~~~~~~~~~~~~ 

Code for reproduction:

extconf.rb

require 'mkmf' create_makefile 'testgem' 

testgem.cc

#include <stdio.h> #include <ruby.h> #include <iostream> VALUE says(VALUE _self, VALUE str) { Check_Type(str, T_STRING); puts(StringValueCStr(str)); return Qnil; } void Init_testgem() { VALUE mod = rb_define_module("Simon"); const int num_args = 1; std::cout << "*** testgem initialized ***" << std::endl; rb_define_module_function(mod, "says", says, num_args); }