g++

问题 I have Ubuntu 12.01 with gcc 4.8.2 and would like to cross compile for the Vortex86DX CPU running an old 2.6.23 kernel. I´m trying the following testing code: #include <iostream> int main() { std::cout << "Hello world" << std::endl; } That is compiled using the following command line: g++ -static-libgcc -static-libstdc++ -march=i586 test.cpp -otest586 When I run the test586 on the target architecture I´m getting this error: $ ./test586 ./teste586: symbol lookup error: ./test586: undefined

问题 I just started using MinGW for Windows. When trying to create executable using g++ a.cpp -o a.exe -std=c++14 for the code below: #include <string> using namespace std; int main() { string x = to_string(123); return 0; } I'm getting following error: C:/mingw/bin/../lib/gcc/mingw32/5.3.0/../../../libmingwex.a(vsnprintf.o):(.text+0x0): multiple definition of vsnprintf C:\Users\..\Local\Temp\cc4sJDvK.o:c:/mingw/include/stdio.h:426: first defined here collect2.exe: error: ld returned 1 exit status

问题 When I disassemble the Chromium binary I notice there are functions named in this pattern: _ZN6webrtc15DecoderDatabase11DecoderInfoD2Ev.part.1 If I give this string to c++filt, the output is webrtc::DecoderDatabase::DecoderInfo::~DecoderInfo() [clone .part.1] So what does this .part.1 suffix really mean? If it indicates there are multiple copies of the same function, why do they need that? Is it due to the requirement of being position independent? I used g++ as the compiler. 回答1: It

问题 I have code of the following structure (which is of course much more complex in reality, especially "Base" is a three-liner, but I've tried to capture the gist of it): template <class T> class A {}; template <class T> class B { public: B(){}; }; template <class T> class C : public B<A<T>> { public: using Base = B<A<T>>; using Base::B; }; static const C<int> c{}; The code compiles fine with g++ via g++ -c test.cpp -std=c++11 However, with clang++ I get an error message I don't really

问题 I have code of the following structure (which is of course much more complex in reality, especially "Base" is a three-liner, but I've tried to capture the gist of it): template <class T> class A {}; template <class T> class B { public: B(){}; }; template <class T> class C : public B<A<T>> { public: using Base = B<A<T>>; using Base::B; }; static const C<int> c{}; The code compiles fine with g++ via g++ -c test.cpp -std=c++11 However, with clang++ I get an error message I don't really

问题 I've got a problem with this code: #include <fstream> struct A { A(std::ifstream input) { //some actions } }; int main() { std::ifstream input("somefile.xxx"); while (input.good()) { A(input); } return 0; } G++ outputs me this: $ g++ file.cpp file.cpp: In function `int main()': file.cpp:17: error: no matching function for call to `A::A()' file.cpp:4: note: candidates are: A::A(const A&) file.cpp:6: note: A::A(std::ifstream) After changing it to this it compile (but that is not solving the

问题 While reading the Clang documentation, I came across the following intriguing tidbit: [1] clang does not support the gcc extension that allows variable-length arrays in structures. This is for a few reasons: one, it is tricky to implement, two, the extension is completely undocumented, and three, the extension appears to be rarely used. Note that clang does support flexible array members (arrays with a zero or unspecified size at the end of a structure). How can this extension be used? My

问题 When gcc 4.1 (using gcov) next line: p = new Class; is reported as 100% branch coverage <-- THIS IS OK for me. Why using gcc 4.4 and higher same line is reportted as: [+ -] p = new Class; (50% branch coverage)... <-- THIS IS a problem for covering 100% !!! Can I set any extra options to newer gcc versions in order to report same branch coverage as gcc 4.1 for single lines as "p = new Class;". Thanks in advance. 回答1: Solved ! We have some C/C++ files with and without exceptions handling, so

问题 I'm learning C++. I'm trying to do an exercise where I define several implementations of a pure virtual class with a single function. I'm having trouble linking the class that uses these implementations. ==> BasicMath.h <== #ifndef BASIC_MATH_H #define BASIC_MATH_H #include<string> #include<vector> class BasicMath { }; #endif // BASIC_MATH_H ==> Operation.h <== #ifndef OPERATION #define OPERATION #include<string> #include<vector> class Operation { public: virtual void perform(std::vector<std:

问题 Can someone please tell me how to create a static library from a .cpp and a .hpp file? Do I need to create the .o and the .a? I would also like to know how can I compile a static library in and use it in other .cpp code. I have header.cpp , header.hpp . I would like to create header.a . Test the header.a in test.cpp . I am using g++ for compiling. 回答1: Create a .o file: g++ -c header.cpp add this file to a library, creating library if necessary: ar rvs header.a header.o use library: g++ main