Nedefinovaná referencia po použití CMAKE na vytvorenie makefile - c ++, makefile, cmake

Môžem vygenerovať svoj projekt CMake, ale nemôžem ho postaviť.

Mám dosť jasnú štruktúru projektu:

├── bin
├── build
├── CMakeLists.txt
├── include
│   └── project
│       ├── base_socket.h
│       ├── tcp_client.h
│       ├── tcp_server.h
│       ├── udp_client.h
│       └── udp_server.h
├── LICENSE.txt
├── README.md
└── src
└── project
├── base_socket.cpp
├── CMakeLists.txt
├── main.cpp
├── tcp_client.cpp
├── tcp_server.cpp
├── udp_client.cpp
└── udp_server.cpp

A pomerne priamy súbor CMakeLists.txt v hornom adresári:

# Project initialization
cmake_minimum_required(VERSION 2.7.2 FATAL_ERROR)

project("cpp_sockets")

# Add include directory
include_directories(include)

# Add subdirectories
add_subdirectory(src/project)

A tiež dosť jednoduchý v src/project/CmakeLists.txt:

set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/bin)
set(HEADER_DIR ${CMAKE_SOURCE_DIR}/include/project)
set(HEADER_FILES
${HEADER_DIR}/base_socket.h
${HEADER_DIR}/tcp_client.h
${HEADER_DIR}/tcp_server.h
${HEADER_DIR}/udp_client.h
${HEADER_DIR}/udp_server.h
)

add_executable(cpp_sockets main.cpp ${HEADER_FILES})

Keď som cd do /build a typ cmake .. to funguje dobre.

Keď to však nasledujem s make, Mám okolo seba veľa strašných chýb undefined reference.

main.cpp:(.text+0x2c6): undefined reference to `UDPClient::UDPClient(int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)"
main.cpp:(.text+0x2eb): undefined reference to `UDPClient::send_message(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)"
main.cpp:(.text+0x359): undefined reference to `UDPServer::UDPServer(int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)"
main.cpp:(.text+0x380): undefined reference to `UDPServer::socket_bind()"
main.cpp:(.text+0x38c): undefined reference to `UDPServer::listen()"
main.cpp:(.text+0x400): undefined reference to `TCPClient::TCPClient(int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)"
main.cpp:(.text+0x40c): undefined reference to `TCPClient::make_connection()"
main.cpp:(.text+0x42b): undefined reference to `TCPClient::send_message(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)"
main.cpp:(.text+0x492): undefined reference to `TCPServer::TCPServer(int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)"
main.cpp:(.text+0x4b9): undefined reference to `TCPServer::socket_bind()"
CMakeFiles/cpp_sockets.dir/main.cpp.o: In function `UDPClient::~UDPClient()":
main.cpp:(.text._ZN9UDPClientD2Ev[_ZN9UDPClientD5Ev]+0x14): undefined reference to `Socket::~Socket()"
CMakeFiles/cpp_sockets.dir/main.cpp.o: In function `UDPServer::~UDPServer()":
main.cpp:(.text._ZN9UDPServerD2Ev[_ZN9UDPServerD5Ev]+0x14): undefined reference to `Socket::~Socket()"
CMakeFiles/cpp_sockets.dir/main.cpp.o: In function `TCPClient::~TCPClient()":
main.cpp:(.text._ZN9TCPClientD2Ev[_ZN9TCPClientD5Ev]+0x14): undefined reference to `Socket::~Socket()"
CMakeFiles/cpp_sockets.dir/main.cpp.o: In function `TCPServer::~TCPServer()":
main.cpp:(.text._ZN9TCPServerD2Ev[_ZN9TCPServerD5Ev]+0x14): undefined reference to `Socket::~Socket()"
collect2: error: ld returned 1 exit status
src/project/CMakeFiles/cpp_sockets.dir/build.make:94: recipe for target "../bin/cpp_sockets" failed
make[2]: *** [../bin/cpp_sockets] Error 1
CMakeFiles/Makefile2:85: recipe for target "src/project/CMakeFiles/cpp_sockets.dir/all" failed
make[1]: *** [src/project/CMakeFiles/cpp_sockets.dir/all] Error 2
Makefile:83: recipe for target "all" failed
make: *** [all] Error 2

main.cpp Súbor vyzerá takto:

  #include "project/udp_server.h"
#include "project/udp_client.h"
#include "project/tcp_client.h"

Prečo by linker nemohol nájsť také referencie?

odpovede:

Vyzerá to ako tvoje src/project/CMakeLists.txt zanedbáva zadanie ďalších súborov cpp, ako udp_server.cpp a udp_client.cpp, ako závislosti spustiteľného súboru cpp_sockets. Musíte to urobiť, aby CMake mohol kompilovať tieto zdrojové súbory; nebude automaticky prísť na to, že ich skompiluje len preto, že ste zahrnuli ich zodpovedajúce hlavičky add_executable vyhlásenie nemusí hovoriť nič o hlavičkách, pretože include_directories velenie sa o to stará.

Vzhľadom na hlavičkové súbory, ktoré váš main.cpp záleží na, jeho add_executable riadok by mal vyzerať takto:

add_executable(cpp_sockets main.cpp udp_server.cpp udp_client.cpp tcp_client.cpp)