Error map
undefined reference to main C/C++: undefined reference to `main' — (.text+0x20) in crt1.o
C/C++ · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (9). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (9)
C/C++: undefined reference to `function' — collect2: error: ld returned 1 exit status
The linker can’t find the definition of a function or variable that was declared and used.
C/C++: fatal error: foo.h: No such file or directory — #include not found
The preprocessor cannot find a header named in `#include`: wrong path, missing include directory (-I), or the library is not inst…
C/C++: multiple definition of `x'; first defined here — ld returned 1 exit status
The linker found the same function or global variable defined in two object files — usually something defined in a header.
C++: undefined reference to `vtable for X' — virtual function not defined
The linker cannot find the class's virtual table, which means at least one virtual member function was declared but never defined…
C/C++: undefined reference to `pthread_create' — missing -pthread (also `dlopen`, `clock_gettime`)
Your program uses threads (or another system library) but the linker was not told to link it.
Make: *** No rule to make target 'foo.c', needed by 'foo.o'. Stop.
`make` was asked to build a file for which there is no rule and no existing file — a missing source, a typo in the Makefile, or a…
Make: Makefile:5: *** missing separator. Stop. (spaces instead of a tab)
A line in the Makefile is neither a rule, a variable assignment nor a tab-indented command — nearly always spaces used where a TA…
CMake Error: Could not find a package configuration file provided by "Foo" (requested version 1.2)
`find_package(Foo)` could not locate the library's CMake config (FooConfig.cmake or FindFoo.cmake), so the library is not install…
MSVC: fatal error LNK1104: cannot open file 'foo.lib' (or 'app.exe' while it is running)
The Visual C++ linker could not open an input library or the output file — the path is wrong, the library is missing, or the .exe…
Two steps away (14)
npm ERR! code ELIFECYCLE / Command failed with exit code 1
An npm script (build, start, test, postinstall) exited with an error. ELIFECYCLE is only the wrapper — the real error is printed…
gyp ERR! build error / node-gyp rebuild failed
A dependency with native C/C++ code couldn’t compile — missing build tools, Python, or an unsupported Node version.
COPY failed: file not found in build context / "/app/x": not found
The Dockerfile COPY refers to a path outside the build context, excluded by .dockerignore, or relative to the wrong directory.
bash: command not found
The shell can’t find an executable with that name in any directory on your PATH.
C++: error: redefinition of 'class X' / multiple definition — missing include guard
The same class, struct or function body was included twice in one translation unit because the header has no include guard.
C++: error: 'optional' in namespace 'std' does not name a template type — wrong -std standard
The standard-library feature you used needs a newer C++ standard than the compiler is currently set to.
C++: error: invalid use of incomplete type 'class X' — forward declaration only
You used a class that has only been forward-declared (so its size and members are unknown) where the full definition is required.
C: warning: implicit declaration of function 'foo' [-Wimplicit-function-declaration]
In C you called a function the compiler has not seen declared — usually a missing `#include`. Newer compilers treat it as an erro…
C++: error: cannot declare variable 'x' to be of abstract type 'Shape' (pure virtual functions)
You tried to create an object of a class that still has pure virtual functions; only a derived class that overrides all of them c…
C++: pure virtual method called — terminate called without an active exception
A pure virtual function was called on an object that is being constructed or destroyed, where the derived part no longer exists.
error while loading shared libraries: libX.so.N: cannot open shared object file: No such file or directory
The program needs a shared library (.so) that isn’t installed or isn’t on the loader’s search path.
C++: terminate called without an active exception — std::thread destroyed while joinable
A `std::thread` object was destroyed (or reassigned) while its thread was still running, so the C++ runtime called `std::terminat…
MSVC: error C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead
Visual C++ treats classic C library functions such as `strcpy`, `sprintf`, `fopen` and `scanf` as deprecated or unsafe and, with…
MSVC: error C2065: 'x': undeclared identifier
Visual C++ met a name it has not seen declared — a typo, a missing header or namespace, or use outside its scope.
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