docs/checks/README-returning-data-from-temporary.md

0001 # returning-data-from-temporary
0002
0003 Warns when returning the data from a `QByteArray` that will soon be destroyed.
0004
0005 ## Examples
0006 ```
0007 QByteArray b = ...;
0008 return b.data();
0009 ```
0010 ```
0011 return funcReturningByteArray().data();
0012 return funcReturningByteArray().constData();
0013 ```
0014
0015
0016 ```
0017 const char * getFoo()
0018 {
0019     QByteArray b = ...;
0020     return b; // QByteArray can implicitly cast to char*
0021 }
0022 ```
0023
0024 ```
0025     const char *c1 = getByteArray();
0026     const char *c2 = str.toUtf8().data();
0027 ```
0028
0029 Note that in some cases it might be fine, since the method can return the data
0030 of a global static QByteArray. However such code is brittle, it could start crashing
0031 if it ceased to be static.