linker-errors

This question already has an answer here: Qt Linker Error: “undefined reference to vtable” [duplicate] 9 answers I'm using Qt Creator 2.0.1 with Qt 4.7.0 (32 bit) on Windows 7 Ultimate 32 bit. Consider the following code, which is a minimum to produce the error: class T : public QObject, public QGraphicsItem { Q_OBJECT public: T() {} QRectF boundingRect() const {return QRectF();} void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) {} }; int main() { T t; return 0; } The above code fragment causes the following linker errors: In function `T': undefined

I have a problem with calling C function from asm project created in visual studio (Win10 x64, Visual Studio 2015). Project consist of one asm file: .586 .model flat, stdcall option casemap:none includelib msvcrt.lib ExitProcess PROTO return:DWORD extern printf:near .data text BYTE "Text", 0 .code main PROC push offset text call printf add esp,4 invoke ExitProcess,0 main ENDP end main When I build project, linker outputs the error: Error LNK2019 unresolved external symbol _printf referenced in function _main@0 Linker output parameters: /OUT:"C:\Users\apple\Documents\SP_Lab7\Debug\SP_Lab7_Demo

I try to compile this cpp code on osx lion but I get an error. #include <iostream> using namespace std; int main (int argc, char *argv[]) { for(int i = 0; i < 10; i++) { cout << "hi"; cout << endl; } return 0; } To compile: cc main.cpp Error: Undefined symbols for architecture x86_64: "std::cout", referenced from: _main in ccBdbc76.o "std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from: _main in ccBdbc76.o "std::basic_ostream<char, std::char_traits<char> >& std::endl<char

This question already has an answer here: undefined reference to sqrt (or other mathematical functions) 5 answers I'm very new to C and I have this code: #include <stdio.h> #include <math.h> int main(void) { double x = 0.5; double result = sqrt(x); printf("The square root of %lf is %lf\n", x, result); return 0; } But when I compile this with: gcc test.c -o test I get an error like this: /tmp/cc58XvyX.o: In function `main': test.c:(.text+0x2f): undefined reference to `sqrt' collect2: ld returned 1 exit status Why does this happen? Is sqrt() not in the math.h header file? I get the same error

I have this simple code: max = (int) sqrt (number); and in the header I have: #include <math.h> But application still says undefined reference to sqrt . Do you see any problem here? It looks like everything should be okay. You may find that you have to link with the math libraries on whatever system you're using, something like: gcc -o myprog myprog.c -L/path/to/libs -lm ^^^ - this bit here. Including headers lets a compiler know about function declarations but it does not necessarily automatically link to the code required to perform that function. Failing that, you'll need to show us your

This question already has an answer here: undefined reference to sqrt (or other mathematical functions) 5 answers I have the following code (stripped down to the bare basics for this question): #include<stdio.h> #include<math.h> double f1(double x) { double res = sin(x); return 0; } /* The main function */ int main(void) { return 0; } When compiling it with gcc test.c I get the following error, and I can't work out why: /tmp/ccOF5bis.o: In function `f1': test2.c:(.text+0x13): undefined reference to `sin' collect2: ld returned 1 exit status However, I've written various test programs that call