diff --git a/scratchpad/dbg.h b/scratchpad/dbg.h
new file mode 100644
index 0000000..9f11809
--- /dev/null
+++ b/scratchpad/dbg.h
@@ -0,0 +1,39 @@
+#ifndef __dbg_h__
+#define __dbg_h__
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+#ifdef NDEBUG
+#define debug(M, ...)
+#else
+#define debug(M, ...) fprintf(stderr, "DEBUG %s:%d: " M "\n",\
+        __FILE__, __LINE__, ##__VA_ARGS__)
+#endif
+
+#define clean_errno() (errno == 0 ? "None" : strerror(errno))
+
+#define log_err(M, ...) fprintf(stderr,\
+        "[ERROR] (%s:%d: errno: %s) " M "\n", __FILE__, __LINE__,\
+        clean_errno(), ##__VA_ARGS__)
+
+#define log_warn(M, ...) fprintf(stderr,\
+        "[WARN] (%s:%d: errno: %s) " M "\n",\
+        __FILE__, __LINE__, clean_errno(), ##__VA_ARGS__)
+
+#define log_info(M, ...) fprintf(stderr, "[INFO] (%s:%d) " M "\n",\
+        __FILE__, __LINE__, ##__VA_ARGS__)
+
+#define check(A, M, ...) if(!(A)) {\
+    log_err(M, ##__VA_ARGS__); errno=0; goto error; }
+
+#define sentinel(M, ...)  { log_err(M, ##__VA_ARGS__);\
+    errno=0; goto error; }
+
+#define check_mem(A) check((A), "Out of memory.")
+
+#define check_debug(A, M, ...) if(!(A)) { debug(M, ##__VA_ARGS__);\
+    errno=0; goto error; }
+
+#endif