diff --git a/TODO b/TODO
index 84364bf1..d4c93106 100644
--- a/TODO
+++ b/TODO
@@ -11,7 +11,7 @@ TODO
 * implement mmap for w32
 * implement sdb_ainc/sdb_adec
 * implement io filters for load/save databases (io wrap)
-* create string pool for a list of sizes 
+* create string pool for a list of sizes
 	newpool (sizeof (char), 10, 100, 1000);
 * Add api to store serialized in memory
 * Add api for raw bytes
@@ -19,7 +19,7 @@ TODO
 * Add support for socket file for memcached api
 * add api to create db without caching it before
 
-Syncronization
+Synchronization
 --------------
  - each key/value have a timestamp of creation/modification
  - sdb_diff() must check both databases and look for removed entries
diff --git a/include/sdb/asserts.h b/include/sdb/asserts.h
new file mode 100644
index 00000000..79c52902
--- /dev/null
+++ b/include/sdb/asserts.h
@@ -0,0 +1,92 @@
+#ifndef SDB_ASSERTS_H
+#define SDB_ASSERTS_H
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+#if defined (__GNUC__) && defined (__cplusplus)
+#define SDB_FUNCTION ((const char*) (__PRETTY_FUNCTION__))
+#elif defined(__STDC__) && defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
+#define SDB_FUNCTION ((const char*) (__func__))
+#elif defined (__GNUC__) || (defined(_MSC_VER) && (_MSC_VER > 1300))
+#define SDB_FUNCTION ((const char*) (__FUNCTION__))
+#else
+#warning Do not know how to get function name in this setup
+#define SDB_FUNCTION ((const char*) ("???"))
+#endif
+
+/*
+ * SDB_CHECKS_LEVEL determines the behaviour of the sdb_return_* set of functions.
+ *
+ * 0: completely disable every function and make them like no-operation
+ * 1: silently enable checks. Check expressions and do return, but do not log anything
+ * 2: enable checks and logging (DEFAULT)
+ * 3: transform them into real assertion
+ */
+#ifndef SDB_CHECKS_LEVEL
+#define SDB_CHECKS_LEVEL 2
+#endif
+
+#if SDB_CHECKS_LEVEL == 0
+
+#define sdb_return_if_fail(expr) do { ; } while(0)
+#define sdb_return_val_if_fail(expr, val) do { ; } while(0)
+
+#elif SDB_CHECKS_LEVEL == 1 || SDB_CHECKS_LEVEL == 2 // SDB_CHECKS_LEVEL
+
+#if SDB_CHECKS_LEVEL == 1
+#define H_LOG_(loglevel, fmt, ...)
+#else
+#define H_LOG_(loglevel, fmt, ...) eprintf (fmt, __VA_ARGS__)
+#endif
+
+/**
+ * sdb_return_if_fail:
+ * @expr: the expression to check
+ *
+ * Verifies that the expression @expr, usually representing a precondition,
+ * evaluates to `true`. If the function returns a value, use
+ * sdb_return_val_if_fail() instead.
+ *
+ * If @expr evaluates to %FALSE, the current function should be considered to
+ * have undefined behaviour (a programmer error). The only correct solution
+ * to such an error is to change the module that is calling the current
+ * function, so that it avoids this incorrect call.
+ *
+ * To make this undefined behaviour visible, if @expr evaluates to %FALSE,
+ * the result is usually that a critical message is logged and the current
+ * function returns.
+ */
+#define sdb_return_if_fail(expr) \
+	do { \
+		if (!(expr)) { \
+			H_LOG_ ("%s: assertion '%s' failed (line %d)", SDB_FUNCTION, #expr, __LINE__); \
+			return; \
+		} \
+	} while (0)
+
+#define sdb_return_val_if_fail(expr, val) \
+	do { \
+		if (!(expr)) { \
+			H_LOG_ ("%s: assertion '%s' failed (line %d)", SDB_FUNCTION, #expr, __LINE__); \
+			return (val); \
+		} \
+	} while (0)
+
+#else // SDB_CHECKS_LEVEL
+
+#include <assert.h>
+
+#define sdb_return_if_fail(expr) do { assert (expr); } while(0)
+#define sdb_return_val_if_fail(expr, val) do { assert (expr); } while(0)
+#define sdb_return_if_reached() do { assert (false); } while(0)
+#define sdb_return_val_if_reached(val) do { assert (false); } while(0)
+
+#endif // SDB_CHECKS_LEVEL
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/include/sdb/sdb.h b/include/sdb/sdb.h
index f9f74e7e..5249f820 100644
--- a/include/sdb/sdb.h
+++ b/include/sdb/sdb.h
@@ -10,6 +10,7 @@
 extern "C" {
 #endif
 
+#include "asserts.h"
 #include "types.h"
 #include "ht.h"
 #include "ls.h"
@@ -192,7 +193,7 @@ SDB_API int sdb_diff_format(char *str, int size, const SdbDiff *diff);
 typedef void (*SdbDiffCallback)(const SdbDiff *diff, void *user);
 
 // Returns true iff the contents of a and b are equal including contained namespaces
-// If cb is non-null, it will be called subsequently with differences. 
+// If cb is non-null, it will be called subsequently with differences.
 SDB_API bool sdb_diff(Sdb *a, Sdb *b, SdbDiffCallback cb, void *cb_user);
 
 // Gets a pointer to the value associated with `key`.