diff --git a/src/_tkagg.cpp b/src/_tkagg.cpp
index bbca8e8d066c..663c06fd0474 100644
--- a/src/_tkagg.cpp
+++ b/src/_tkagg.cpp
@@ -231,13 +231,13 @@ bool load_tcl_tk(T lib)
 {
     // Try to fill Tcl/Tk global vars with function pointers.  Return whether
     // all of them have been filled.
-    if (void* ptr = dlsym(lib, "Tcl_SetVar")) {
+    if (auto ptr = dlsym(lib, "Tcl_SetVar")) {
         TCL_SETVAR = (Tcl_SetVar_t)ptr;
     }
-    if (void* ptr = dlsym(lib, "Tk_FindPhoto")) {
+    if (auto ptr = dlsym(lib, "Tk_FindPhoto")) {
         TK_FIND_PHOTO = (Tk_FindPhoto_t)ptr;
     }
-    if (void* ptr = dlsym(lib, "Tk_PhotoPutBlock")) {
+    if (auto ptr = dlsym(lib, "Tk_PhotoPutBlock")) {
         TK_PHOTO_PUT_BLOCK = (Tk_PhotoPutBlock_t)ptr;
     }
     return TCL_SETVAR && TK_FIND_PHOTO && TK_PHOTO_PUT_BLOCK;