sysrap/tests/ConstExprTest.cc

0001 // name=ConstExprTest ; gcc $name.cc -std=c++11 -lstdc++ -o /tmp/$name && /tmp/$name
0002
0003 /**
0004
0005 https://stackoverflow.com/questions/29844028/explain-constexpr-with-const-charconst
0006
0007
0008 https://en.cppreference.com/w/cpp/language/constexpr
0009     constexpr is since C++11
0010
0011     The constexpr specifier declares that it is possible to evaluate the value of
0012     the function or variable at compile time. Such variables and functions can then
0013     be used where only compile time constant expressions are allowed (provided that
0014     appropriate function arguments are given).
0015
0016
0017 *In summary think of constexpr as more const than const : a compile time constant*
0018
0019 **/
0020
0021
0022 struct ConstExprTest
0023 {
0024     static constexpr const char* STR = "some useful string constant";
0025 };
0026
0027
0028 #include <iostream>
0029
0030 int main()
0031 {
0032     std::cout << ConstExprTest::STR << std::endl ;
0033     return 0 ;
0034 }
0035