--- SAOImageDS9/tkmpeg/tkmpeg.C.orig 2018-05-28 13:32:25.211025703 +0200 +++ SAOImageDS9/tkmpeg/tkmpeg.C 2018-05-28 13:33:30.768864460 +0200 @@ -73,7 +73,7 @@ int TkMPEG::create(int argc, const char* argv[]) { if (argc == 8) { - if (*argv[2] == '\0') { + if (*argv[2] == NULL) { Tcl_AppendResult(interp, "bad filename", NULL); return TCL_ERROR; } @@ -127,7 +127,7 @@ int TkMPEG::add(int argc, const char* argv[]) { - if (*argv[2] == '\0') { + if (*argv[2] == NULL) { Tcl_AppendResult(interp, "bad image name", NULL); return TCL_ERROR; }