diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h
index 8928f68..cd22dfb 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -128,4 +128,6 @@
 const char *osmo_quote_str(const char *str, int in_len);
 const char *osmo_quote_str_buf(const char *str, int in_len, char *buf, size_t bufsize);
 
+uint32_t osmo_isqrt32(uint32_t x);
+
 /*! @} */