Crystal Multiple Shared Library PoC

This directory demonstrates loading multiple Crystal-built shared libraries in one Ruby process.

The PoC intentionally keeps the boundary to C ABI functions only. Crystal objects, exceptions, strings, arrays and procs don't cross the shared-library boundary.

Build

From this directory:

cd poc
./build.sh

The build script is intentionally simple and assumes it is run from the poc directory. By default it uses ../.build/crystal. You can override the compiler path:

CRYSTAL=../bin/crystal ./build.sh

Run

Ruby FFI version:

ruby run_ffi.rb

Expected output includes three loaded libraries and independent results from alpha_add, beta_fib and gamma_tak.

Each library defines its own Worker class internally. The class name is the same in all three libraries on purpose; the export maps keep those Crystal symbols local to each shared object.

Inspect Exports

nm -D --defined-only build/libalpha.so
nm -D --defined-only build/libbeta.so
nm -D --defined-only build/libgamma.so

Only the prefixed C ABI symbols should be exported:

alpha_*
beta_*
gamma_*

This includes the small public entry points such as alpha_init, alpha_add and alpha_last_error.

Crystal runtime symbols such as __crystal_main, __crystal_once, String, Array or main should not appear in nm -D --defined-only.

The internal Worker symbols should also be absent from nm -D, while they can still be seen as local symbols with plain nm --defined-only.