First you have to understand the C99 inline model – perhaps there is something wrong with your headers. There are two kind of definitions for inline functions with external (non-static) linkage External definition This definition of a function can only appear once in the whole program, in a designated TU. It provides an exported function … Read more
The problem is you are not linking against the Ws2_32.lib library. To fix this you can add that to your additional dependencies tab of linker/Input settings for your project. Alternatively (as pointed out by SChepurin in the comments) you can add #pragma comment(lib, “Ws2_32.lib”) to a source file of your project.
strlwr() is not standard C function. Probably it’s provided by one implementation while the other compiler you use don’t. You can easily implement it yourself: #include <string.h> #include<ctype.h> char *strlwr(char *str) { unsigned char *p = (unsigned char *)str; while (*p) { *p = tolower((unsigned char)*p); p++; } return str; }
These functions are part of the C++ exception handling support for GCC. GCC supports two kinds of exception handling, one which is based on calls to setjmp and longjmp (sjlj exception handling), and another which is based on the DWARF debugging info format (DW2 exception handling). These sorts of linker errors will occur is you … Read more
Normally this sort of failure happens when compiling your C++ code by invoking the C front-end. The gcc you execute understands and compiles the file as C++, but doesn’t link it with the C++ libraries. Example: $ gcc example.cpp Undefined symbols for architecture x86_64: “std::cout”, referenced from: _main in ccLTUBHJ.o “std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> … Read more
How are you doing the compiling and linking? You’ll need to specify both files, something like: gcc testpoint.c point.c …so that it knows to link the functions from both together. With the code as it’s written right now, however, you’ll then run into the opposite problem: multiple definitions of main. You’ll need/want to eliminate one … Read more
It is because the unit generated by MOC isn’t included in the linking process. Or maybe it isn’t generated at all. The first thing I’d do is to put the class declaration in a separate header file, perhaps the build system isn’t scanning implementation files. Another possibility is that the class in question once didn’t … Read more
If Obstacle is an abstract base class, then make sure you declare all its virtual methods “pure virtual”: virtual void Method() = 0; The = 0 tells the compiler that this method must be overridden by a derived class, and might not have its own implementation. If the class contains any non-pure virtual functions, then … Read more
The math library must be linked in when building the executable. How to do this varies by environment, but in Linux/Unix, just add -lm to the command: gcc test.c -o test -lm The math library is named libm.so, and the -l command option assumes a lib prefix and .a or .so suffix.