common FEATURE ly_strcat() to concatenate strings
diff --git a/src/common.h b/src/common.h
index 1c18a13..718a83b 100644
--- a/src/common.h
+++ b/src/common.h
@@ -442,6 +442,16 @@
LY_ERR ly_munmap(void *addr, size_t length);
/**
+ * @brief Concatenate formating string to the @p dest.
+ *
+ * @param[in, out] dest String to be concatenated by @p format.
+ * Note that the input string can be reallocated during concatenation.
+ * @param[in] format Formating string (as for printf) which is supposed to be added after @p dest.
+ * @return LY_SUCCESS or LY_EMEM.
+ */
+LY_ERR ly_strcat(char **dest, const char *format, ...);
+
+/**
* @brief (Re-)Allocation of a ([sized array](@ref sizedarrays)).
*
* Increases the size information.