How to enable C++11 in Qt Creator?

According to this site add

CONFIG += c++11

to your .pro file (see at the bottom of that web page). It requires Qt 5.

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The other answers, suggesting

QMAKE_CXXFLAGS += -std=c++11 (or QMAKE_CXXFLAGS += -std=c++0x)

also work with Qt 4.8 and gcc / clang.

Add this to your .pro file

QMAKE_CXXFLAGS += -std=c++11

or

CONFIG += c++11

As an alternative for handling both cases addressed in Ali's excellent answer, I usually add

# With C++11 support
greaterThan(QT_MAJOR_VERSION, 4){    
CONFIG += c++11
} else {
QMAKE_CXXFLAGS += -std=c++0x
}

to my project files. This can be handy when you don't really care much about which Qt version is people using in your team, but you want them to have C++11 enabled in any case.