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What is an undefined reference/unresolved external symbol error and how do I fix it?
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Error LNK2019 unresolved external symbol _WinMain#16 referenced in function "int __cdecl invoke_main(void)" (?invoke_main##YAHXZ)
(4 answers)
Linker error: unresolved external symbol _WinMain#16 when building console application [duplicate]
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Closed 1 year ago.
I'm trying to build a cmake project that uses WinHTTP. Below is my cmakelists.txt file
cmake_minimum_required(VERSION 3.19)
project(Mandarin_EXE_Updator)
set(SOURCE_FILES main.cpp)
set(WIN32 True)
OPTION(WINHTTP ON)
add_executable(Mandarin_Updator WIN32 ${SOURCE_FILES})
target_link_libraries(winhttp)
I've tried doing link_libraries and target_link_libraries but with no luck. I think i need to use link_libraries, but with the full path to the lib file.
below is the output of cmake --build .
Microsoft (R) Build Engine version 16.8.3+39993bd9d for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.
MSVCRTD.lib(exe_winmain.obj) : error LNK2019: unresolved external symbol WinMain referenced in function "int __cdecl invoke_main(void)
" (?invoke_main##YAHXZ) [C:\Users\srika\OneDrive\Desktop\Mandarin.EXE\Mandarin Updater\build\Mandarin_Updator.vcxproj]
C:\Users\srika\OneDrive\Desktop\Mandarin.EXE\Mandarin Updater\build\Debug\Mandarin_Updator.exe : fatal error LNK1120: 1 unresolved ext
ernals [C:\Users\srika\OneDrive\Desktop\Mandarin.EXE\Mandarin Updater\build\Mandarin_Updator.vcxproj]
Related
Problem
I am getting linker errors when building my project. The project has no trouble finding wxWidgets headers. I have looked at the wxWidgets minimal example and recreated it in order to verify that my build from source worked properly. I used cmake in VSCode to do the build using the cmake extension.
The wxWidgets cmake generated fine and the build of wxwidgets appears to have gone fine. I am using the Visual Studio 2022 amd64 toolset to do the compile. (I installed VS2022 Community Edition for the compiler only).
It looks like it is building DLL for the libraries. I would prefer static libraries but for an initial run I didnt think it mattered. I link my application to wx::net wx::core wx::base as recommended. I thought that this would take care of linking when I go to build.
When I go to build my overall application utilizing the wxWidgets library, I get these linker errors.
What am I doing wrong here? Im obviously not configuring something correctly for it to find the library, but I am kind of stumped here.
Linker Errors
[build] ProjectName.obj : error LNK2001: unresolved external symbol "protected: static class wxAppConsole * (__cdecl* wxAppConsoleBase::ms_appInitFn)(void)" -snipped-
[build] ProjectName.obj : error LNK2001: unresolved external symbol "protected: static class wxAppConsole * wxAppConsoleBase::ms_appInstance" -snipped-
[build] MainWindow.obj : error LNK2001: unresolved external symbol "void (__cdecl* wxTheAssertHandler)(class wxString const &,int,class wxString const &,class wxString const &,class wxString const &)"-snipped-
[build] MainWindow.obj : error LNK2001: unresolved external symbol "bool wxTrapInAssert" (?wxTrapInAssert##3_NA) -snipped-
[build] MainWindow.obj : error LNK2001: unresolved external symbol "class wxMBConv * wxConvLibcPtr" (?wxConvLibcPtr##3PEAVwxMBConv##EA) -snipped-
[build] MainWindow.obj : error LNK2001: unresolved external symbol "public: static unsigned __int64 const wxString::npos" (?npos#wxString##2_KB)-snipped-
[build] MainWindow.obj : error LNK2001: unresolved external symbol "class wxSize const wxDefaultSize" (?wxDefaultSize##3VwxSize##B)-snipped-
[build] MainWindow.obj : error LNK2001: unresolved external symbol "class wxPoint const wxDefaultPosition" (?wxDefaultPosition##3VwxPoint##B)-snipped-
[build] MainWindow.obj : error LNK2001: unresolved external symbol "char const * const wxFrameNameStr" (?wxFrameNameStr##3QBDB)-snipped-
[build] C:\path\to\executable\ProjectName.exe : fatal error LNK1120: 9 unresolved externals -snipped-
[build] Build finished with exit code 1
Project Layout
Pretty basic project layout. I am building a GUI application and I am logically separating out the ui source code.
This is basically a recreation of the minimal wxWidgets example where you have an entry point (Projectname.hpp and ProjectName.cpp provide this) and a main window/frame (MainWindow.hpp and MainWindow.cpp provide this). The ProjectName application will do the wxIMPLEMENT_APP(ProjectName) and will hold a pointer to a MainWindow. The MainWindow is shown using the OnInit Function.
ProjectName/
build/
external/
wxWidgets-3.1.6/
-CMakeLists.txt
source/
ui/
-MainWindow.hpp
-MainWindow.cpp
-ProjectName.hpp
-ProjectName.cpp
-CMakeLists.txt
I have compiled the wxWidgets library using their cmake instructions for using a subdirectory in cmake so I could add it to my project. Here are the contents of the CMakeLists.txt's
ProjectName CMakeLists.txt
cmake_minimum_required(VERSION 3.23)
set(MAJOR 0)
set(MINOR 0)
set(PATCH 1)
#Setup Project
project(ProjectNameProject VERSION ${MAJOR}.${MINOR}.${PATCH}
DESCRIPTION "ProjectName Descrip"
LANGUAGES CXX)
add_executable(ProjectName WIN32 ${PROJECT_SOURCE_DIR}/source/ProjectName.cpp
${PROJECT_SOURCE_DIR}/source/ui/MainWindow.cpp)
target_include_directories(ProjectName PRIVATE ${PROJECT_SOURCE_DIR}/source)
target_include_directories(ProjectName PRIVATE ${PROJECT_SOURCE_DIR}/source/ui)
target_link_libraries(ProjectName PRIVATE wx::net wx::core wx::base)
add_subdirectory(${CMAKE_SOURCE_DIR}/external)
ProjectName/externals CMakeLists.txt
cmake_minimum_required(VERSION 3.23)
add_subdirectory(${CMAKE_SOURCE_DIR}/external/wxWidgets-3.1.6)
Update
I changed the Cmake option for building a shared library (DLL) and set it to OFF. When this is done, it builds a static library (LIB). This seemed to fix my linking issues.
Per Igor's suggestion, I took another look at the minimal sample CMakeLists.txt and noticed they used the following line for linking
target_link_libraries(${PROJECT_NAME} ${wxWidgets_LIBRARIES})
Perhaps my line (below) is the way to link statically and does not work with DLLs?
target_link_libraries(ProjectName PRIVATE wx::net wx::core wx::base)
If someone could help me understand why having it build statically fixed it, I would 100% accept that answer.
I changed the Cmake option for building a shared library (DLL) and set it to OFF. When this is done, it builds a static library (LIB). This seemed to fix my linking issues.
Unfortunately I do no see anyone able to chime in to help understand why this is the solution, but I am going to select this as an answer for others coming to this in the future.
If I see any updates that answer the question of "why" I will accept their answer.
I'm building a C++ GStreamer project with CMake which depends on GStreamer, GLIB, Libsoup and json-glib. I'm new to CMake and having trouble setting up my project. I've managed to include many of the dependencies but some seem to remain unresolved even though they are part of GStreamer. All GStreamer methods and types are resolved with the exception of SDP and WebRTC. They are, to my understanding, part of GStreamer and are also located inside of the directory which GMake correctly "finds".
These are the errors that are occurring when trying to build the project.
[build] error LNK2019: unresolved external symbol __imp_gst_sdp_message_new referenced in function "void __cdecl soup_websocket_message_cb(struct _SoupWebsocketConnection *,enum SoupWebsocketDataType,struct _GBytes *,void *)" (?soup_websocket_message_cb##YAXPEAU_SoupWebsocketConnection##W4SoupWebsocketDataType##PEAU_GBytes##PEAX#Z)
[build] error LNK2019: unresolved external symbol __imp_gst_sdp_message_parse_buffer referenced in function "void __cdecl soup_websocket_message_cb(struct _SoupWebsocketConnection *,enum SoupWebsocketDataType,struct _GBytes *,void *)" (?soup_websocket_message_cb##YAXPEAU_SoupWebsocketConnection##W4SoupWebsocketDataType##PEAU_GBytes##PEAX#Z)
[build] error LNK2019: unresolved external symbol __imp_gst_sdp_message_as_text referenced in function "void __cdecl on_offer_created_cb(struct _GstPromise *,void *)" (?on_offer_created_cb##YAXPEAU_GstPromise##PEAX#Z)
[build] error LNK2019: unresolved external symbol __imp_gst_webrtc_session_description_get_type referenced in function "void __cdecl on_offer_created_cb(struct _GstPromise *,void *)" (?on_offer_created_cb##YAXPEAU_GstPromise##PEAX#Z)
[build] error LNK2019: unresolved external symbol __imp_gst_webrtc_session_description_new referenced in function "void __cdecl soup_websocket_message_cb(struct _SoupWebsocketConnection *,enum SoupWebsocketDataType,struct _GBytes *,void *)" (?soup_websocket_message_cb##YAXPEAU_SoupWebsocketConnection##W4SoupWebsocketDataType##PEAU_GBytes##PEAX#Z)
[build] error LNK2019: unresolved external symbol __imp_gst_webrtc_session_description_free referenced in function "void __cdecl on_offer_created_cb(struct _GstPromise *,void *)" (?on_offer_created_cb##YAXPEAU_GstPromise##PEAX#Z)
This is my CMakeLists.txt
# CMakeList.txt : CMake project for stream-project, include source and define
# project specific logic here.
#
cmake_minimum_required (VERSION 3.8)
project (stream-project LANGUAGES CXX)
# Packages
find_package(PkgConfig REQUIRED)
# Add source to this project's executable.
add_executable (${PROJECT_NAME} "main.cpp" "main.h")
# Search all modules that we so desire to use and "include_directories"
pkg_search_module(GST REQUIRED gstreamer-1.0 gstreamer-sdp-1.0 gstreamer-video-1.0 gstreamer-app-1.0 gstreamer-webrtc-1.0)
pkg_search_module(GLIB REQUIRED glib-2.0)
pkg_search_module(LIBSOUP REQUIRED libsoup-2.4)
pkg_search_module(JSONGLIB REQUIRED json-glib-1.0)
include_directories(
${GST_INCLUDE_DIRS}
${GLIB_INCLUDE_DIRS}
${LIBSOUP_INCLUDE_DIRS}
${JSONGLIB_INCLUDE_DIRS}
)
# Link target directories and libraries
target_link_directories(${PROJECT_NAME} PRIVATE
${GST_LIBRARY_DIRS}
${GLIB_LIBRARY_DIRS}
${LIBSOUP_LIBRARY_DIRS}
${JSONGLIB_LIBRARY_DIRS}
)
target_link_libraries(${PROJECT_NAME} PRIVATE
${GST_LIBRARIES}
${GLIB_LIBRARIES}
${LIBSOUP_LIBRARIES}
${JSONGLIB_LIBRARIES}
)
message(STATUS ${GST_INCLUDE_DIRS})
I've managed to solve it by using a premade find script I found online.
https://chromium.googlesource.com/external/Webkit/+/master/Source/cmake/FindGStreamer.cmake
It creates all necessary defines which I then include and link.
These are the defaults as specified in the FindGStreamer.cmake file
FIND_GSTREAMER_COMPONENT(GSTREAMER_APP gstreamer-app-1.0 gst/app/gstappsink.h gstapp-1.0)
FIND_GSTREAMER_COMPONENT(GSTREAMER_AUDIO gstreamer-audio-1.0 gst/audio/audio.h gstaudio-1.0)
FIND_GSTREAMER_COMPONENT(GSTREAMER_FFT gstreamer-fft-1.0 gst/fft/gstfft.h gstfft-1.0)
FIND_GSTREAMER_COMPONENT(GSTREAMER_PBUTILS gstreamer-pbutils-1.0 gst/pbutils/pbutils.h gstpbutils-1.0)
FIND_GSTREAMER_COMPONENT(GSTREAMER_VIDEO gstreamer-video-1.0 gst/video/video.h gstvideo-1.0)
I extended those above with:
FIND_GSTREAMER_COMPONENT(GSTREAMER_SDP gstreamer-sdp-1.0 gst/sdp/sdp.h gstsdp-1.0)
FIND_GSTREAMER_COMPONENT(GSTREAMER_WEBRTC gstreamer-webrtc-1.0 gst/webrtc/webrtc.h gstwebrtc-1.0)
I'm getting a lot of erros LNK2019, after I use the nmake command on VS2015 console:
kmeans.cpp.obj : error LNK2019: unresolved external symbol clGetPlatformIDs > referenced in function "int __cdecl initialize(int)" (?initialize##YAHH#Z) kmeans.cpp.obj : error LNK2019: unresolved external symbol clCreateContextFromType referenced in function "int __cdecl initialize(int)" (?initialize##YAHH#Z) kmeans.cpp.obj : error LNK2019: unresolved external symbol clReleaseContext referenced in function "int __cdecl shutdown(void)" (?shutdown##YAHXZ) kmeans.cpp.obj : error LNK2019: unresolved external symbol clGetContextInfo referenced in function "int __cdecl initialize(int)" (?initialize##YAHH#Z) kmeans.cpp.obj : error LNK2019: unresolved external symbol clCreateCommandQueue referenced in function "int __cdecl initialize(int)" (?initialize##YAHH#Z) kmeans.cpp.obj : error LNK2019: unresolved external symbol clReleaseCommandQueue referenced in function "int __cdecl shutdown(void)" (?shutdown##YAHXZ)
My PC Specs and OS:
Windows 10 x64
Core i7 4790k
GTX 1080.
NVidia CUDA SDK Installed.
Does anybody know how to fix it, or faced the same problem? Already tried the #pragma with OpenCL Lib but that didnt work.
Already tried to change application type from Windows to console on VS, but that didn't work too.
My CMakeLists.txt is:
cmake_minimum_required( VERSION 2.6 )
project( kmeans )
find_package( OpenCL REQUIRED )
include_directories(${OpenCL_INCLUDE_DIRS})
add_executable( kmeans kmeans.cpp )
target_link_libraries( kmeans ${OPENCL_LIBRARIES} )
Link of the code repository that I'm using:
https://github.com/davidebaltieri31/OpenCL_kMeans
My exact steps:
Open VS2015 console.
Type "cmake . -G "NMake Makefiles""
Type nmake.
Then I get the LNK2019 Erros (Full screenshot here: http://puu.sh/uNOWQ/66e8d134a1.png).
I've been having problems with cmake and Visual Studio 2013 with SFML. When I try and compile my program, I'm getting unresolved externals for everything that uses SFML. I've had problems with this on multiple machines, and also with some other libraries in some case.
I'm using the following command to generate my Visual Studio Project (inside a VisualStudioProject folder):
Z:/Coding/cmake/cmake-3.1.1-win32-x86/bin/cmake.exe -G "Visual Studio 12" ..
And this is my CMakeLists.txt (it's actually generated from a python script I wrote, but I doubt that's important). I can confirm that all the libraries are being found correctly.
cmake_minimum_required (VERSION 2.6)
set( CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/bin)
set( CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/lib )
set( CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/lib )
project(Game)
include_directories( Z:/Coding/Libraries/SFML/SFML-2.2/include Z:/Coding/Game/src/win32 Z:/Coding/Game/src )
find_library( SFML-GRAPHICS NAMES sfml-graphics PATHS Z:/Coding/Libraries/SFML/SFML-2.2/lib NO_DEFAULT_PATH )
find_library( SFML-WINDOW NAMES sfml-window PATHS Z:/Coding/Libraries/SFML/SFML-2.2/lib NO_DEFAULT_PATH )
find_library( SFML-SYSTEM NAMES sfml-system PATHS Z:/Coding/Libraries/SFML/SFML-2.2/lib NO_DEFAULT_PATH )
add_executable( win32 "Z:/Coding/Game/apps/win32.cpp" )
target_link_libraries( win32 ${SFML-GRAPHICS} ${SFML-WINDOW} ${SFML-SYSTEM} )
This is my simple SFML test program:
#include <string>
#include <iostream>
#include <SFML/Graphics.hpp>
using namespace std;
int main(int argc, char *argv[])
{
sf::RenderWindow window;
window.create(sf::VideoMode(1280, 1024), "Test");
while (true)
{
sf::Event ev;
while (window.pollEvent(ev))
{
if (ev.type = sf::Event::EventType::Closed)
{
window.close();
exit(1);
}
}
}
std::string hello = "Hello";
cout << hello << endl;
}
And I'm getting unresolved externals for the following:
Error 1 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: __thiscall sf::String::String(char
const *,class std::locale const &)"
(__imp_??0String#sf##QAE#PBDABVlocale#std###Z) referenced in function
_main Z:\Coding\Game\VisualStudioProject\win32.obj win32
Error 2 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: __thiscall sf::String::~String(void)"
(__imp_??1String#sf##QAE#XZ) referenced in function
_main Z:\Coding\Game\VisualStudioProject\win32.obj win32
Error 3 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: __thiscall
sf::VideoMode::VideoMode(unsigned int,unsigned int,unsigned int)"
(__imp_??0VideoMode#sf##QAE#III#Z) referenced in function
_main Z:\Coding\Game\VisualStudioProject\win32.obj win32
Error 4 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: void __thiscall
sf::Window::create(class sf::VideoMode,class sf::String const
&,unsigned int,struct sf::ContextSettings const &)"
(__imp_?create#Window#sf##QAEXVVideoMode#2#ABVString#2#IABUContextSettings#2##Z)
referenced in function
_main Z:\Coding\Game\VisualStudioProject\win32.obj win32
Error 5 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: void __thiscall
sf::Window::close(void)" (__imp_?close#Window#sf##QAEXXZ) referenced
in function _main Z:\Coding\Game\VisualStudioProject\win32.obj win32
Error 6 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: bool __thiscall
sf::Window::pollEvent(class sf::Event &)"
(__imp_?pollEvent#Window#sf##QAE_NAAVEvent#2##Z) referenced in
function _main Z:\Coding\Game\VisualStudioProject\win32.obj win32
Error 7 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: __thiscall
sf::RenderWindow::RenderWindow(void)"
(__imp_??0RenderWindow#sf##QAE#XZ) referenced in function
_main Z:\Coding\Game\VisualStudioProject\win32.obj win32
Error 8 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: virtual __thiscall
sf::RenderWindow::~RenderWindow(void)"
(__imp_??1RenderWindow#sf##UAE#XZ) referenced in function
_main Z:\Coding\Game\VisualStudioProject\win32.obj win32
Error 9 error LNK1120: 8 unresolved
externals Z:\Coding\Game\bin\Debug\win32.exe win32
I've used this same style of script before with SFML in the past on Windows with an earlier VS successfully (at least I recall I have) so I think it's a new thing with VS 2013, but I'm utterly stumped.
Thanks in advance.
Note: This is a simplistic example. This style of CMakeLists.txt is generated by script because the main code-base it's used on is very large (originally Linux based, hence why '/'s are used everywhere).
This certainly looks like you've not actually linked any of the three SFML libs successfully.
If the find_library calls in the CMakeLists.txt had failed to find the libraries, then CMake would output a fatal error which I'm sure you'd have mentioned.
So my best guess is that you're trying to link the 64-bit version of the SFML libs, while your CMake command specifies a 32-bit build.
To create a 64-bit build, just run:
cmake -G "Visual Studio 12 Win64" ..
You'll need to empty your build folder to change the generator from "Visual Studio 12" to "Visual Studio 12 Win64".
See the docs for further info about the VS generator.
Stab in the dark:
Try running
Z:/Coding/cmake/cmake-3.1.1-win32-x86/bin/cmake.exe -G "Visual Studio 12 2013 Win64"
This will force it to do all the linking in a 64-bit environment. I am presuming you're using a 64-bit computer. I'm further presuming you have a 64-bit version of SFML. (It's the future, I think these are safe assumptions).
CMake will try and pick a "sensible" default as per http://www.cmake.org/cmake/help/v3.0/generator/Visual%20Studio%2012%202013.html but sometimes you want to force it to pick the right option.
I'm trying to write some C++ code for Windows 7 which will connect to a mobile broadband network. When I run the first example at http://msdn.microsoft.com/en-us/library/ee677092(v=VS.85).aspx I get the following when compiling within Visual Studio:
testII.obj : error LNK2001: unresolved external symbol _CLSID_MbnInterfaceManager
testII.obj : error LNK2001: unresolved external symbol _IID_IMbnInterfaceManager
or when I compile with the "cl" command at the command prompt I get:
test.cpp
Microsoft (R) Incremental Linker Version 10.00.30319.01
Copyright (C) Microsoft Corporation. All rights reserved.
/out:test.exe
test.obj
test.obj : error LNK2019: unresolved external symbol _CLSID_MbnInterfaceManager referenced in function _main
test.obj : error LNK2019: unresolved external symbol _IID_IMbnInterfaceManager referenced in function _main
test.exe : fatal error LNK1120: 2 unresolved externals
It would seem I need to link so some library somewhere, can anyone tell me which library and how to link it? Do these errors have anything to do with the mbnapi.idl requirement?
Thanks a lot, appreciate it
What you need to do is include mbnapi_uuid.lib