home.md

@@ -8,4 +8,12 @@ The official libcoap repository is https://github.com/obgm/libcoap.
 git fetch --tags https://github.com/obgm/libcoap.git '+refs/heads/*:refs/remotes/origin/github/*'
 git push --tags origin '+refs/remotes/origin/github/*:refs/heads/github/*'
 git fetch origin
-```
\ No newline at end of file
+```
+
+## Information for Phoenix Developers on using libcoap
+
+### Adding data to a coap message
+
+*libcoap* provides a call ```coap_add_data()``` which behaves similar as memcpy, i.e., you specify the number of bytes that you want to add.
+
+Attention:  In case you want to add a string to a coap message and you use ```strlen()``` to determine the number of bytes in the string, keep in mind that ```strlen()``` dos *not* account for the terminating null-character.  So, if you want to add the terminating null-character as well via ```coap_add_data()```, you have to pass ```strlen() + 1``` to ```coap_add_data()```.