gcc4.9

Consider this code: #include <iostream> int main() { int i{10.1}; // narrowing, should not compile std::cout << i << std::endl; } According to the C++11 standard, it should not compile (narrowing in brace initialization is forbidden.) Now, compiling with g++4.9.2 -std=c++11 only emits a warning warning: narrowing conversion of '1.01e+1' from 'double' to 'int' inside { } [-Wnarrowing] Removing the -std=c++11 flag results in a warning regarding the brace init, but not any narrowing: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11 On the other hand, g++5 doesn't

This question follows this previous question about the definedness of memcpy(0, 0, 0) , which has been conclusively determined to be undefined behavior. As the linked question shows, the answer hinges on the contents of C11's clause 7.1.4:1 Each of the following statements applies unless explicitly stated otherwise in the detailed descriptions that follow: If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, […]) […] the behavior is undefined. […] The standard function

In gcc-4.9 changes it says: UndefinedBehaviorSanitizer (ubsan), a fast undefined behavior detector, has been added and can be enabled via -fsanitize=undefined. Various computations will be instrumented to detect undefined behavior at runtime. UndefinedBehaviorSanitizer is currently available for the C and C++ languages. I looked at this question ( A C++ implementation that detects undefined behavior? ) but it seems fairly outdated. This link ( http://gcc.gnu.org/ml/gcc-patches/2013-06/msg00264.html ) has some information on it, but it's several months old. This is an attempt to add the

I have seen various answer here that depicts Strange behavior of pow function in C. But I Have something different to ask here. In the below code I have initialized int x = pow(10,2) and int y = pow(10,n) (int n = 2) . In first case it when I print the result it shows 100 and in the other case it comes out to be 99 . I know that pow returns double and it gets truncated on storing in int , but I want to ask why the output comes to be different. CODE1 #include<stdio.h> #include<math.h> int main() { int n = 2; int x; int y; x = pow(10,2); //Printing Gives Output 100 y = pow(10,n); //Printing

This question already has an answer here: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version CXXABI_1.3.8' not found [closed] 8 answers When I run my program following a compile, I get the following error: ./prog: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version CXXABI_1.3.8' not found (required by ./prog) ./prog: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version GLIBCXX_3.4.19' not found (required by ./prog) ./prog: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.20' not found (required by /home/arman/lib/boost_1_55_0/stage/lib/libboost_serialization.so.1.55.0) I have both

Below program has been written to fetch the "Day" information using the C++11 std::regex_match & std::regex_search . However, using the first method returns false and second method returns true (expected). I read the documentation and already existing SO question related to this, but I do not understand the difference between these two methods and when we should use either of them? Can they both be used interchangeably for any common problem? Difference between regex_match and regex_search? #include<iostream> #include<string> #include<regex> int main() { std::string input{ "Mon Nov 25 20:54:36

gcc 4.9 allows the following code, but gcc 4.8 and clang 3.5.0 reject it. void foo(auto c) { std::cout << c.c_str(); } I get warning: ISO C++ forbids use of 'auto' in parameter declaration [-Wpedantic] in 4.9 but in 4.8 and clang I get error: parameter declared 'auto' . Yes, this is an extension. It's likely to be added to C++17 as part of the 'concepts' proposal, I believe. This is Concepts Lite speak for template<class T> void foo(T c) { std::cout << c.c_str(); } The auto just replaces the more verbose template<class T> . Similarly, you can write void foo(Sortable c) as a shorthand for