Clarify QByteArray::size() documentation.

QTBUG-25438

Change-Id: I8cf9bfb295195548b6f7d4410682e4d675181a65
Reviewed-by: Denis Dzyubenko <denis.dzyubenko@nokia.com>

src/corelib/doc/snippets/code/src_corelib_tools_qbytearray.cpp

@@ -416,6 +416,25 @@ strcpy(data, text.data());
 delete [] data;
 //! [47]
 
+//! [48]
+QByteArray ba1("ca\0r\0t");
+ba1.size();                     // Returns 2.
+ba1.constData();                // Returns "ca" with terminating \0.
+
+QByteArray ba2("ca\0r\0t", 3);
+ba2.size();                     // Returns 3.
+ba2.constData();                // Returns "ca\0" with terminating \0.
+
+QByteArray ba3("ca\0r\0t", 4);
+ba3.size();                     // Returns 4.
+ba2.constData();                // Returns "ca\0r" with terminating \0.
+
+const char cart[] = {'c', 'a', '\0', 'r', '\0', 't'};
+QByteArray ba4(QByteArray::fromRawData(cart, 6));
+ba4.size();                     // Returns 6.
+ba4.constData();                // Returns "ca\0r\0t" without terminating \0.
+//! [48]
+
 }
 
 

src/corelib/tools/qbytearray.cpp

@@ -681,7 +681,12 @@ static inline char qToLower(char c)
 
     A QByteArray can embed '\\0' bytes. The size() function always
     returns the size of the whole array, including embedded '\\0'
-    bytes. If you want to obtain the length of the data up to and
+    bytes, but excluding the terminating '\\0' added by QByteArray.
+    For example:
+
+    \snippet code/src_corelib_tools_qbytearray.cpp 48
+
+    If you want to obtain the length of the data up to and
     excluding the first '\\0' character, call qstrlen() on the byte
     array.