3 files changed, 23 insertions, 0 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 397f273..e9bc4d6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,7 @@ set(SRC
   src/list.c
   src/main.c
   src/template.c
+  src/util.c
 )
 
 add_executable(msg ${SRC})
diff --git a/include/util.h b/include/util.h
new file mode 100644
index 0000000..58c1f58
--- /dev/null
+++ b/include/util.h
@@ -0,0 +1,6 @@
+#ifndef __UTIL_H
+#define __UTIL_H
+
+void xstrcat(char *s1, char *s2);
+
+#endif
diff --git a/src/util.c b/src/util.c
new file mode 100644
index 0000000..4863e29
--- /dev/null
+++ b/src/util.c
@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <util.h>
+
+void
+xstrcat(char *s1, char *s2)
+{
+  size_t a = strlen(s1);
+  size_t b = strlen(s2);
+  size_t size_ab = a + b + 1;
+
+  s1 = realloc(s1, size_ab);
+
+  memcpy(s1 + a, s2, b + 1);
+}