Boost.Ref example 1 is a Boost.Ref example.
Operating system(s) or programming environment(s)
Lubuntu 15.04 (vivid)
Qt Creator 3.1.1
- G++ 4.9.2
Libraries used:
STL: GNU ISO C++ Library, version
4.9.2
Qt project file: ./CppBoostRefExample1/CppBoostRefExample1.pro
include(../../ConsoleApplication.pri) #Or use the code below # QT += core # QT += gui # greaterThan(QT_MAJOR_VERSION, 4): QT += widgets # CONFIG += console # CONFIG -= app_bundle # TEMPLATE = app # CONFIG(release, debug|release) { # DEFINES += NDEBUG NTRACE_BILDERBIKKEL # } # QMAKE_CXXFLAGS += -std=c++11 -Wall -Wextra -Weffc++ # unix { # QMAKE_CXXFLAGS += -Werror # } include(../../Libraries/Boost.pri) #Or use the code below # win32 { # INCLUDEPATH += \ # ../../Libraries/boost_1_54_0 # } SOURCES += main.cpp
#include <cassert> #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #include <boost/ref.hpp> #pragma GCC diagnostic pop int main() { int a = 42; //Reference-wrap a const boost::reference_wrapper<int> b(a); //Const-reference-wrap the reference-wrap of a const boost::reference_wrapper<const int> c(b); //Cannot do a non-const wrap around const-wrap c //const boost::reference_wrapper<int> d(c); //Won't compile assert(a == 42 && a == b && b == c); ++a; assert(a == 43 && a == b && b == c); ++b; assert(a == 44 && a == b && b == c); //Cannot modify a const-wrap //++c; //Won't compile }