Close used OpenCL library

When we finalize the OpenCL system we would want to close the library again.

Improved logs using the nts variant

Author: jenshannoschwalm

src/common/dlopencl.c

@@ -1,6 +1,6 @@
 /*
     This file is part of darktable,
-    Copyright (C) 2011-2023 darktable developers.
+    Copyright (C) 2011-2026 darktable developers.
 
     darktable is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -22,6 +22,10 @@
 #include "common/dynload.h"
 #include "common/dlopencl.h"
 
+#ifdef __APPLE__
+#include <dlfcn.h>
+#endif
+
 #include <assert.h>
 #include <signal.h>
 #include <stdio.h>
@@ -36,6 +40,19 @@ static const char *ocllib[] = { "/System/Library/Frameworks/OpenCL.framework/Ver
 static const char *ocllib[] = { "libOpenCL", "libOpenCL.so", "libOpenCL.so.1", NULL };
 #endif
 
+void dt_dlopencl_close(dt_dlopencl_t *ocl)
+{
+  free(ocl->symbols);
+  g_free(ocl->library);
+#ifndef __APPLE__
+  if(!g_module_close(ocl->gmodule))
+    dt_print(DT_DEBUG_OPENCL, "Couldn't close OpenCL library");
+#else
+  if(dlclose(ocl->gmodule))
+    dt_print(DT_DEBUG_OPENCL, "Couldn't close OpenCL library");
+#endif
+  free(ocl);
+}
 
 /* only for debugging: default noop function for all unassigned function pointers */
 void dt_dlopencl_noop(void)
@@ -63,9 +80,9 @@ dt_dlopencl_t *dt_dlopencl_init(const char *name)
     library = name;
     module = dt_gmodule_open(library);
     if(module == NULL)
-      dt_print(DT_DEBUG_OPENCL, "[dt_dlopencl_init] could not find specified opencl runtime library '%s'", library);
+      dt_print_nts(DT_DEBUG_OPENCL | DT_DEBUG_VERBOSE, "[dt_dlopencl_init] could not find specified opencl runtime library '%s'\n", library);
     else
-      dt_print(DT_DEBUG_OPENCL | DT_DEBUG_VERBOSE, "[dt_dlopencl_init] found specified opencl runtime library '%s'", library);
+      dt_print_nts(DT_DEBUG_OPENCL | DT_DEBUG_VERBOSE, "[dt_dlopencl_init] found specified opencl runtime library '%s'\n", library);
   }
   else
   {
@@ -75,15 +92,18 @@ dt_dlopencl_t *dt_dlopencl_init(const char *name)
       library = *iter;
       module = dt_gmodule_open(library);
       if(module == NULL)
-        dt_print(DT_DEBUG_OPENCL, "[dt_dlopencl_init] could not find default opencl runtime library '%s'", library);
+        dt_print_nts(DT_DEBUG_OPENCL | DT_DEBUG_VERBOSE, "[dt_dlopencl_init] could not find default opencl runtime library '%s'\n", library);
       else
-        dt_print(DT_DEBUG_OPENCL | DT_DEBUG_VERBOSE, "[dt_dlopencl_init] found default opencl runtime library '%s'", library);
+        dt_print_nts(DT_DEBUG_OPENCL | DT_DEBUG_VERBOSE, "[dt_dlopencl_init] found default opencl runtime library '%s'\n", library);
       iter++;
     }
   }
 
   if(module == NULL)
+  {
+    dt_print_nts(DT_DEBUG_OPENCL, "[dt_dlopencl_init] could not find any opencl runtime library\n");
     return NULL;
+  }
 
   /* now bind symbols */
   ocl = malloc(sizeof(dt_dlopencl_t));
@@ -98,6 +118,7 @@ dt_dlopencl_t *dt_dlopencl_init(const char *name)
 
   if(ocl->symbols == NULL)
   {
+    dt_print_nts(DT_DEBUG_OPENCL, "[dt_dlopencl_init] could not find symbols in opencl runtime library\n");
     free(ocl);
     free(module);
     return NULL;
@@ -209,7 +230,9 @@ dt_dlopencl_t *dt_dlopencl_init(const char *name)
   ocl->have_opencl = success;
 
   if(!success)
-    dt_print(DT_DEBUG_OPENCL, "[opencl_init] could not load all required symbols from library");
+    dt_print_nts(DT_DEBUG_OPENCL, "[opencl_init] could not load all required symbols from library\n");
+  else
+    ocl->gmodule = module->gmodule;
 
   free(module);
 

src/common/dlopencl.h

@@ -1,6 +1,6 @@
 /*
     This file is part of darktable,
-    Copyright (C) 2011-2023 darktable developers.
+    Copyright (C) 2011-2026 darktable developers.
 
     darktable is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -215,6 +215,11 @@ typedef struct dt_dlopencl_t
   gboolean have_opencl;
   dt_dlopencl_symbols_t *symbols;
   char *library;
+#ifndef __APPLE__
+  GModule *gmodule;
+#else
+  void *gmodule;
+#endif
 } dt_dlopencl_t;
 
 /* default noop function for all unassigned function pointers */
@@ -223,6 +228,9 @@ void dt_dlopencl_noop(void);
 /* dynamically load OpenCL library and bind needed functions */
 dt_dlopencl_t *dt_dlopencl_init(const char *);
 
+/* dynamically close OpenCL library opened by dt_dlopencl_init() */
+void dt_dlopencl_close(dt_dlopencl_t *ocl);
+
 #endif // HAVE_OPENCL
 
 // clang-format off

src/common/opencl.c

@@ -1659,9 +1659,7 @@ void dt_opencl_cleanup(dt_opencl_t *cl)
 
   if(cl->dlocl)
   {
-    free(cl->dlocl->symbols);
-    g_free(cl->dlocl->library);
-    free(cl->dlocl);
+    dt_dlopencl_close(cl->dlocl);
   }
 
   free(cl->dev);