You have compiled your code with references to the correct math.h header file, but when you attempted to link it, you forgot the option to include the math library. As a result, you can compile your .o object files, but not build your executable. As Paul has already mentioned add “-lm” to link with the … Read more
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 … Read more
A link-time error like these messages can be for many of the same reasons as for more general uses of the linker, rather than just having compiled a Fortran program. Some of these are covered in the linked question about C++ linking and in another answer here: failing to specify the library, or providing them … Read more
Compiling a C++ program takes place in several steps, as specified by 2.2 (credits to Keith Thompson for the reference): The precedence among the syntax rules of translation is specified by the following phases [see footnote]. Physical source file characters are mapped, in an implementation-defined manner, to the basic source character set (introducing new-line characters … Read more
Any time you add a new call to the Q_OBJECT macro, you need to run qmake again. The vtables issue you’re referring to is directly related to that. Just run qmake and you should be good to go assuming there are no other issues in your code.