Tcl_IncrRefCount(validPathPtr);
    }

    str = Tcl_GetString(validPathPtr);
    len = validPathPtr->length;
    Tcl_UtfToExternalDString(NULL, str, len, &ds);
    len = Tcl_DStringLength(&ds) + sizeof(char);
    if (strlen(Tcl_DStringValue(&ds)) < len - sizeof(char)) {
	/* See bug [3118489]: NUL in filenames */
	Tcl_DecrRefCount(validPathPtr);
	Tcl_DStringFree(&ds);
	return NULL;
    }
    Tcl_DecrRefCount(validPathPtr);
    nativePathPtr = ckalloc(len);
    memcpy(nativePathPtr, Tcl_DStringValue(&ds), len);

    Tcl_DStringFree(&ds);
    return nativePathPtr;
}