1 files changed, 42 insertions, 1 deletions
diff --git a/md/notes/undefined_c/titles.md b/md/notes/undefined_c/titles.md
index 2c5bcd1..92b35ab 100644
--- a/md/notes/undefined_c/titles.md
+++ b/md/notes/undefined_c/titles.md
@@ -239,10 +239,51 @@ Now size of structure will be 32.
 
 All results on amd64, other arch may differ.
 
+### How to shoot leg
+Forget that struct size is not consistent. 
 
+### Recursion
+
+Recursion is technique that could be useful to write shorter code 
+and deal with cycles. One thing that recursion suffer is that it consumes
+stack memory and its have default limit on platform.
+
+```c
+#include <stdio.h>
+#include <stdlib.h>
+
+int fun_r(int i) {
+	printf("val %d\n",i);
+	fun_r(i+1);
+	return 0;
+}
+
+int main() 
+{
+	fun_r(0);
+}
+```
+
+Program will fail after its reach out of stack range.
+When increase the default stack limit it go more further.
+
+
+Check default stack size
+
+```
+ulimit -s
+```
+
+Set stack size
+
+```
+ulimit -s 16384
+```
 
-### Recursion  
 ### Macro
+
+
+
 ### Signed/Unsigned
 ### Pointers
 ### Endianess