fatal error: filesystem: No such file or directory

[thekendalmiller]

I'm seeing this compilation issue on on Amazon Linux 2 (redhat like) with gcc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-17).

From googling a bit, it looks like it might be because some gcc have filesystem as experimental. It looks like there are macros to detect the namespace https://stackoverflow.com/a/53366603

[root@ip-REDACTED]# cat /etc/os-release
NAME="Amazon Linux"
VERSION="2"
ID="amzn"
ID_LIKE="centos rhel fedora"
VERSION_ID="2"
PRETTY_NAME="Amazon Linux 2"
ANSI_COLOR="0;33"
CPE_NAME="cpe:2.3:o:amazon:amazon_linux:2"
HOME_URL="https://amazonlinux.com/"
SUPPORT_END="2025-06-30"

[root@ip-REDACTED]# gcc --version
gcc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-17)
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

"g++ -o conftest -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0/x86_64-linux -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0/ruby/backward -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0 -I. -I/opt/rubies/ruby-3.0.6/include     conftest.cc  -L. -L/opt/rubies/ruby-3.0.6/lib -Wl,-rpath,/opt/rubies/ruby-3.0.6/lib -L. -L/opt/rubies/ruby-3.0.6/lib  -fstack-protector-strong -rdynamic -Wl,-export-dynamic -Wl,--no-as-needed     -Wl,-rpath,/opt/rubies/ruby-3.0.6/lib -L/opt/rubies/ruby-3.0.6/lib -lruby  -lm   -lc"
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main(int argc, char **argv)
4: {
5:   return !!argv[argc];
6: }
/* end */

"g++ -E -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0/x86_64-linux -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0/ruby/backward -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0 -I. -I/opt/rubies/ruby-3.0.6/include    -O3 -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wduplicated-cond -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wwrite-strings -Wimplicit-fallthrough=0 -Wmissing-noreturn -Wno-cast-function-type -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-packed-bitfield-compat -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wunused-variable  -fPIC  conftest.cc -o conftest.i"
cc1plus: warning: command line option '-Wimplicit-function-declaration' is valid for C/ObjC but not for C++
cc1plus: warning: command line option '-Wimplicit-int' is valid for C/ObjC but not for C++
conftest.cc:3:10: fatal error: rice/rice.hpp: No such file or directory
 #include <rice/rice.hpp>
          ^~~~~~~~~~~~~~~
compilation terminated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <rice/rice.hpp>
/* end */

"g++ -E -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0/x86_64-linux -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0/ruby/backward -I/opt/rubies/ruby-3.0.6/include/ruby-3.0.0 -I. -I/opt/rubies/ruby-3.0.6/include    -O3 -ggdb3 -Wall -Wextra -Wdeprecated-declarations -Wduplicated-cond -Wimplicit-function-declaration -Wimplicit-int -Wmisleading-indentation -Wpointer-arith -Wwrite-strings -Wimplicit-fallthrough=0 -Wmissing-noreturn -Wno-cast-function-type -Wno-constant-logical-operand -Wno-long-long -Wno-missing-field-initializers -Wno-overlength-strings -Wno-packed-bitfield-compat -Wno-parentheses-equality -Wno-self-assign -Wno-tautological-compare -Wno-unused-parameter -Wno-unused-value -Wsuggest-attribute=format -Wsuggest-attribute=noreturn -Wunused-variable  -fPIC -I/var/app/bundle/ruby/3.0.0/gems/rice-4.1.0/include conftest.cc -o conftest.i"
cc1plus: warning: command line option '-Wimplicit-function-declaration' is valid for C/ObjC but not for C++
cc1plus: warning: command line option '-Wimplicit-int' is valid for C/ObjC but not for C++
In file included from conftest.cc:3:0:
/var/app/bundle/ruby/3.0.0/gems/rice-4.1.0/include/rice/rice.hpp:1208:10: fatal error: filesystem: No such file or directory
 #include <filesystem>
          ^~~~~~~~~~~~
compilation terminated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: #include <rice/rice.hpp>
/* end */

I can confirm for these servers that filesystem is in /usr/include/c++/7/experimental/filesystem

[jasonroelofs]

Thanks for the links! Adding the testing macros should be simple enough. Looks like we only pull that in for the possibility of catching std::filesystem::filesystem_error.

[thekendalmiller]

I also needed to change this line to have_library('stdc++fs')
https://github.com/jasonroelofs/rice/blob/59b03953e91f681849a20121614bcdb1114c86d8/lib/mkmf-rice.rb#L129