From 84b98c362a04bfc4c776a42147d75662a14601c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Blanchon?=
 <bblanchon@users.noreply.github.com>
Date: Thu, 28 Apr 2016 08:26:31 +0200
Subject: [PATCH] Updated FAQ (markdown)

---
 FAQ.md | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/FAQ.md b/FAQ.md
index 05339f2..00b659d 100644
--- a/FAQ.md
+++ b/FAQ.md
@@ -10,7 +10,8 @@
   * [What's the best way to use the library?](#whats-the-best-way-to-use-the-library)
   * [How to write a function that works with both `JsonArray` and `JsonObject`?](#how-to-write-a-function-that-works-with-both-jsonarray-and-jsonobject)
 * [Part 2 - Serialization questions](#part-2---serialization-questions)
-  * [How do I create complex nested objects?](#how-do-i-create-complex-nested-objects)
+  * [How to compute the JSON length?](#how-to-compute-the-JSON-length)
+  * [How to create complex nested objects?](#how-to-create-complex-nested-objects)
   * [The first serialization succeeds, why do the next ones fail?](#the-first-serialization-succeeds-why-do-the-next-ones-fail)
 * [Part 3 - Deserialization questions](#part-3---deserializationparsing-questions)
   * [Can I parse data from a stream?](#can-i-parse-data-from-a-stream)
@@ -282,7 +283,31 @@ See issue [#195](https://github.com/bblanchon/ArduinoJson/issues/195) and [#196]
 
 
 
-### How do I create complex nested objects?
+### How to compute the JSON length?
+
+Use `measureLength()` to compute the number of characters that will be printed by `printTo()`.
+
+Use `measurePrettyLength()` to compute the number of characters that will be printed by `prettyPrintTo()`.
+
+None of these methods include the zero terminator.
+So if you need to allocate a buffer, don't forget to add 1 to the size.
+
+```c++
+StaticJsonBuffer<200> jsonBuffer;
+JsonObject& root = jsonBuffer.createObject();
+root["hello"] = world;
+
+size_t len = root.measureLength(); // returns 17
+
+size_t size = len+1;
+char json[size];
+root.printTo(json, size); // writes {"hello":"world"}
+```
+
+See issues [#75](https://github.com/bblanchon/ArduinoJson/issues/75), [#94](https://github.com/bblanchon/ArduinoJson/issues/94), [#166](https://github.com/bblanchon/ArduinoJson/issues/166), [#178](https://github.com/bblanchon/ArduinoJson/issues/178) and [#268](https://github.com/bblanchon/ArduinoJson/issues/268).
+
+
+### How to create complex nested objects?
 
 To create a nested object, call `createNestedObject()`.
 To create a nested array, call `createNestedArray()`.