From c82e69a997dd3bb02ad2e59515937428ba9379ae Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Tue, 23 Feb 2021 15:18:38 -0500
Subject: [PATCH] Added import-shared-object

---
 CHANGELOG.md    |  1 +
 runtime.c       | 20 +++++++++++++-------
 scheme/eval.sld |  5 +++++
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index be517947..3102e5f6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 Features
 
 - Arthur Maciel added `opaque?` and `opaque-null?` predicates to `(cyclone foreign)`.
+- Added `import-shared-object` to `(scheme eval)` to allow loading a third party C shared library.
 
 Bug Fixes
 
diff --git a/runtime.c b/runtime.c
index f7954ed4..705bfc08 100644
--- a/runtime.c
+++ b/runtime.c
@@ -6946,14 +6946,20 @@ void Cyc_import_shared_object(void *data, object cont, object filename, object e
   }
   dlerror();    /* Clear any existing error */
 
-  entry_pt = (function_type) dlsym(handle, string_str(entry_pt_fnc));
-  if (entry_pt == NULL) {
-    snprintf(buffer, 256, "%s, %s, %s", string_str(filename), string_str(entry_pt_fnc), dlerror());
-    make_utf8_string(data, s, buffer);
-    Cyc_rt_raise2(data, "Unable to load symbol", &s);
+  if (string_len(entry_pt_fnc) == 0) {
+    // No entry point so this is a third party library.
+    // Just call into our continuation
+    return_closcall1(data, cont, boolean_t);
+  } else {
+    entry_pt = (function_type) dlsym(handle, string_str(entry_pt_fnc));
+    if (entry_pt == NULL) {
+      snprintf(buffer, 256, "%s, %s, %s", string_str(filename), string_str(entry_pt_fnc), dlerror());
+      make_utf8_string(data, s, buffer);
+      Cyc_rt_raise2(data, "Unable to load symbol", &s);
+    }
+    mclosure1(clo, entry_pt, cont);
+    entry_pt(data, 0, &clo, &clo);
   }
-  mclosure1(clo, entry_pt, cont);
-  entry_pt(data, 0, &clo, &clo);
 }
 
 /** Read */
diff --git a/scheme/eval.sld b/scheme/eval.sld
index 5a8f14a7..d7d2f0a6 100644
--- a/scheme/eval.sld
+++ b/scheme/eval.sld
@@ -26,6 +26,8 @@
     %import
     imported?
     %set-import-dirs!
+    import-shared-object
+    ;; Macros
     *defined-macros* 
     get-macros
     macro:macro?
@@ -810,6 +812,9 @@
 (define (imported? lis)
   (c:lib-loaded? (lib:name->unique-string (lib:list->import-set lis))))
 
+(define (import-shared-object filename)
+  (c:import-shared-obj filename ""))
+
 ;; Wrapper around the actual shared object import function
 (define-c c:import-shared-obj
   "(void *data, int argc, closure _, object k, object fn, object entry_fnc)"