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Compile problem with ruby preview 2.4.0 - possibly related to the upcoming Bignum/Fixnum change/unification #17

ghost opened this Issue Jun 24, 2016 · 1 comment


1 participant

ghost commented Jun 24, 2016

Hello Aaron and others,

I have tried latest ruby 2.4.0-preview1. It may be not worth the
time to invest for previews - however had, perhaps even in the
final 2.4.0 release, this issue may persist, hence why I report

Command (works perfectly fine on ruby 2.3.1 by the way):

gem install syck-1.1.0.gem

Building native extensions. This could take a while...

ERROR: Error installing syck-1.1.0.gem:
ERROR: Failed to build gem native extension.

current directory: /Programs/Ruby/2.4.0preview1/lib/ruby/gems/2.4.0/gems/syck-1.1.0/ext/syck
/Programs/Ruby/2.4.0preview1/bin/ruby -r ./siteconf20160624-21263-8tem4.rb extconf.rb

checking for st.h... yes
creating Makefile

To see why this extension failed to compile, please check the mkmf.log which can be found here:


current directory: /Programs/Ruby/2.4.0preview1/lib/ruby/gems/2.4.0/gems/syck-1.1.0/ext/syck
make "DESTDIR=" clean

current directory: /Programs/Ruby/2.4.0preview1/lib/ruby/gems/2.4.0/gems/syck-1.1.0/ext/syck
make "DESTDIR="
compiling bytecode.c
compiling emitter.c
compiling gram.c
compiling handler.c
compiling implicit.c
compiling node.c
compiling rubyext.c

The error appears to be:

rubyext.c: In function 'syck_resolver_transfer':
rubyext.c:1165:34: error: 'rb_cBignum' undeclared (first use in this function)
                 if ( subclass == rb_cBignum )
rubyext.c:1165:34: note: each undeclared identifier is reported only once for 
each function it appears in make: *** [Makefile:241: rubyext.o] Error 1

make failed, exit code 2

Gem files will remain installed in /Programs/Ruby/2.4.0preview1/lib/ruby/gems/2.4.0/gems/syck-1.1.0 for inspection.
Results logged to /Programs/Ruby/2.4.0preview1/lib/ruby/gems/2.4.0/extensions/x86_64-linux/2.4.0/syck-1.1.0/gem_make.out

I am not sure why this error happens, perhaps because of the Bignum/Fixnum change? My C is
very weak but perhaps there may have to be a check added to see whether rb_cBignum is
available or not. But I am just guessing here really, anyway.

At any rate, this is just a small report, feel free to close it at any time.



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hsbt Jun 25, 2016


@shevegen I fixed this at #18


hsbt commented Jun 25, 2016

@shevegen I fixed this at #18

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