1 files changed, 11 insertions, 0 deletions
diff --git a/generic/tclBasic.c b/generic/tclBasic.c
index 21fb2e2..e09ea1e 100644
--- a/generic/tclBasic.c
+++ b/generic/tclBasic.c
@@ -928,6 +928,17 @@ Tcl_CreateInterp(void)
 	    TclPrecTraceProc, NULL);
     TclpSetVariables(interp);
 
+#ifdef TCL_THREADS
+    /*
+     * The existence of the "threaded" element of the tcl_platform array
+     * indicates that this particular Tcl shell has been compiled with threads
+     * turned on. Using "info exists tcl_platform(threaded)" a Tcl script can
+     * introspect on the interpreter level of thread safety.
+     */
+
+    Tcl_SetVar2(interp, "tcl_platform", "threaded", "1", TCL_GLOBAL_ONLY);
+#endif
+
     /*
      * Register Tcl's version number.
      * TIP #268: Full patchlevel instead of just major.minor