Implement C interop regression test for dynamic loading and runtime symbol invocation (dlopen/dlsym)

• Type: test
• Status: in-progress
• Track: C (C frontend interop testing)
• Owner: Antigravity
• Opened: 2026-06-28

Motivation

To test dynamic loading of libraries "at will" at runtime and calling resolved functions through function pointers, we need a regression test for the POSIX dynamic linking loader interface (dlfcn.h).

This test will exercise:

1. Importing <dlfcn.h> and linking against libdl.so.2 automatically.
2. Loading libm.so.6, libz.so.1, and libcrypt.so.1 at runtime using dlopen.
3. Resolving symbol addresses (cos, zlibVersion, crypt) using dlsym.
4. Defining custom procedural types (e.g. cdecl function signatures) in Pascal.
5. Casting resolved symbol pointers (Pointer) to procedural types.
6. Invoking the runtime-resolved function pointers (passing floats and strings back and forth).
7. Releasing the library handles using dlclose.

Scope

1. Test implementation:
   • Create test/test_c_dlopen.pas.
   • Verify dynamic invocation of cos(0.0) = 1.0.
   • Verify dynamic invocation of zlibVersion().
   • Verify dynamic invocation of crypt(...).
2. Integration:
   • Wire the test into the test target of the Makefile.

Acceptance

• test/test_c_dlopen.pas compiles successfully.
• Executing the binary dynamically loads the target libraries, invokes the functions, asserts correct values, and exits with 0.

Log

• 2026-06-28 — ticket opened and taken.