+#ifdef NDEBUG
+/*
+ * Force usage of the assertion condition to prevent unused variable warnings
+ * when `assert()` are disabled by the `NDEBUG` definition.
+ */
+# define ARGPAR_ASSERT(_cond) ((void) sizeof((void) (_cond), 0))
+#else
+# include <assert.h>
+# define ARGPAR_ASSERT(_cond) assert(_cond)
+#endif