unix: it's legal for dlsym() to return NULL

A symbol name can map to NULL. Check dlerror() to see if a real error happened.
joyent · Dec 18, 2011 · feb267e · feb267e · wereHamster · Dec 18, 2011
1 parent e9235a3
commit feb267e
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Showing 2 changed files with 10 additions and 3 deletions.
diff --git a/include/uv.h b/include/uv.h
@@ -1250,7 +1250,8 @@ UV_EXTERN uv_err_t uv_dlopen(const char* filename, uv_lib_t* library);
 UV_EXTERN uv_err_t uv_dlclose(uv_lib_t library);
 
 /*
- * Retrieves a data pointer from a dynamic library.
+ * Retrieves a data pointer from a dynamic library. It is legal for a symbol to
+ * map to NULL.
  */
 UV_EXTERN uv_err_t uv_dlsym(uv_lib_t library, const char* name, void** ptr);
 

diff --git a/src/unix/dl.c b/src/unix/dl.c
@@ -53,8 +53,14 @@ uv_err_t uv_dlclose(uv_lib_t library) {
 
 
 uv_err_t uv_dlsym(uv_lib_t library, const char* name, void** ptr) {
-  void* address = dlsym(library, name);
-  if (address == NULL) {
+  void* address;
+
+  /* Reset error status. */
+  dlerror();
+
+  address = dlsym(library, name);
+
+  if (dlerror()) {
     return uv_inval_;
   }