Ruby in C using Singleton module crashes-CodePudding

I was trying to implement a project using Ruby's C API which led me to the following problem. I have a script that requires the Singleton module and noticed that my program always crashes, so I boiled the issue down to using the following code:

#include <ruby.h>

int main(int argc, char* argv[])
{
  ruby_init();
  rb_require("singleton");
  return ruby_cleanup(0);
}

Compile it using

gcc test.c `pkg-config --cflags --libs ruby`

Whenever I run this I get a segfault at the rb_require("singleton").

ruby: [BUG] Segmentation fault at 0x00000c
ruby 2.3.0p0 (2015-12-25) [i386-linux-gnu]

-- Control frame information -----------------------------------------------
c:0001 p:0000 s:0002 E:001788 (none) [FINISH]


-- Machine register context ------------------------------------------------
  GS: 0x00000063  FS: 0x00000000  ES: 0x0000002b  DS: 0x0000002b EDI: 0x098163e8
 ESI: 0xf7f7f230 EBP: 0xff8004c8 ESP: 0xff8004c4 EBX: 0x00000006 EDX: 0x00000000
 ECX: 0x00000006 EAX: 0x09816410 TRA: 0x0000000e ERR: 0x00000004 EIP: 0xf7d29d76
  CS: 0x00000023 EFL: 0x00010212 UES: 0xff8004c4  SS: 0x0000002b

-- C level backtrace information -------------------------------------------
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7e49c41]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7e49e33]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7d267cc]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7dd4493]
linux-gate.so.1 [0xf7f9e090]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7d29d76]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7d2ae68]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7d2b2d1]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7d26e2b]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7d28734]
/lib/i386-linux-gnu/libruby-2.3.so.2.3 [0xf7d30903]
/lib/i386-linux-gnu/libruby-2.3.so.2.3(rb_require 0x3a) [0xf7d309da]
./a.out(main 0x23) [0x80485ee]

I tried this with several Ruby versions (2.3, 2.5 and 2.7) on different machines and always run into the same issue, so at the moment I think I am doing something wrong.

Can someone explain what might be the issue here?

CodePudding user response：

In order to use rb_require you need to call ruby_init_loadpath first.

So, this works:

int main(int argc, char* argv[])
{
  ruby_init();
  ruby_init_loadpath();

  rb_require("singleton");

  return ruby_cleanup(0);
}

While researching your problem I found these to be useful:
Running Ruby in C
How do you fully initialize an embedded ruby VM in a C application?