+
+#ifdef _WIN32
+/** Junk for arranging thread-specific callbacks on Windows. This is
+ * necessarily platform and compiler-specific. Windows supports up
+ * to 1088 keys. Let's assume nobody opens more than 64 environments
+ * in a single process, for now. They can override this if needed.
+ */
+#ifndef MAX_TLS_KEYS
+#define MAX_TLS_KEYS 64
+#endif
+static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];
+static int mdb_tls_nkeys;
+
+static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
+{
+ int i;
+ switch(reason) {
+ case DLL_PROCESS_ATTACH: break;
+ case DLL_THREAD_ATTACH: break;
+ case DLL_THREAD_DETACH:
+ for (i=0; i<mdb_tls_nkeys; i++) {
+ MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
+ mdb_env_reader_dest(r);
+ }
+ break;
+ case DLL_PROCESS_DETACH: break;
+ }
+}
+#ifdef __GNUC__
+#ifdef _WIN64
+const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
+#else
+PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
+#endif
+#else
+#ifdef _WIN64
+/* Force some symbol references.
+ * _tls_used forces the linker to create the TLS directory if not already done
+ * mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.
+ */
+#pragma comment(linker, "/INCLUDE:_tls_used")
+#pragma comment(linker, "/INCLUDE:mdb_tls_cbp")
+#pragma const_seg(".CRT$XLB")
+extern const PIMAGE_TLS_CALLBACK mdb_tls_callback;
+const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
+#pragma const_seg()
+#else /* WIN32 */
+#pragma comment(linker, "/INCLUDE:__tls_used")
+#pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
+#pragma data_seg(".CRT$XLB")
+PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
+#pragma data_seg()
+#endif /* WIN 32/64 */
+#endif /* !__GNUC__ */