--- a/th_string.c	Wed Feb 17 13:44:57 2016 +0200
+++ b/th_string.c	Wed Feb 17 14:13:22 2016 +0200
@@ -11,6 +11,19 @@
 
 /* Implementation of strdup() with a NULL check
  */
+size_t th_strlen(const char *str)
+{
+    size_t len;
+    assert(str != NULL);
+
+    for (len = 0; *str; str++) len++;
+
+    return len;
+}
+
+
+/* Implementation of strdup() with a NULL check
+ */
 char *th_strdup(const char *src)
 {
     char *res;

--- a/th_string.h	Wed Feb 17 13:44:57 2016 +0200
+++ b/th_string.h	Wed Feb 17 14:13:22 2016 +0200
@@ -58,6 +58,8 @@
 
 /* Normal NUL-terminated string functions
  */
+size_t   th_strlen(const char *str);
+
 char    *th_strdup(const char *src);
 char    *th_strndup(const char *src, const size_t n);
 char    *th_strdup_trim(const char *, const int flags);