setting up the helloworld example for cmake build; building with ixwebsocket library

[timbo100]

Please pardon my ignorance. I'm new to CMake.

I appear to have successfully built and install ixwebsocket with the final sudo make install

I've created a main.cpp file from the example shown at here

I've placed the main.cpp in a directory and added a CMakeLists.txt file:

cmake_minimum_required(VERSION 3.14)
set (CMAKE_CXX_STANDARD 14)
project(test1 C CXX)
find_package(ixwebsocket)
add_executable(test1 main.cpp)
target_link_libraries (test1 ixwebsocket)
install(TARGETS test1 DESTINATION bin)

I'm sure my CMakeLists.txt file is the problem.

When I run cmake .. from the ../build dir I don't get any cmake errors.

However, when i run make I get a lot of link errors, "undefined references". I know what this typically means but I'm not sure how to get the CMakefile insures that the objects are found.

Here's a brief list of the kinds of errors I'm getting:

tim-testing/build$ make
[ 50%] Building CXX object CMakeFiles/test1.dir/main.cpp.o
[100%] Linking CXX executable test1
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXWebSocketPerMessageDeflateCodec.cpp.o): in function `bool ix::WebSocketPerMessageDeflateCompressor::compressData<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&) [clone .part.0]':
IXWebSocketPerMessageDeflateCodec.cpp:(.text+0x6f): undefined reference to `deflate'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXWebSocketPerMessageDeflateCodec.cpp.o): in function `ix::WebSocketPerMessageDeflateCompressor::~WebSocketPerMessageDeflateCompressor()':
IXWebSocketPerMessageDeflateCodec.cpp:(.text+0x3e0): undefined reference to `deflateEnd'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXWebSocketPerMessageDeflateCodec.cpp.o): in function `ix::WebSocketPerMessageDeflateCompressor::init(unsigned char, bool)':
IXWebSocketPerMessageDeflateCodec.cpp:(.text+0x42a): undefined reference to `deflateInit2_'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXWebSocketPerMessageDeflateCodec.cpp.o): in function `ix::WebSocketPerMessageDeflateCompressor::compress(ix::IXWebSocketSendData const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)':
IXWebSocketPerMessageDeflateCodec.cpp:(.text+0x627): undefined reference to `deflate'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXWebSocketPerMessageDeflateCodec.cpp.o): in function `ix::WebSocketPerMessageDeflateDecompressor::~WebSocketPerMessageDeflateDecompressor()':

[.....]

 [clone .part.0]':
IXWebSocketPerMessageDeflateCodec.cpp:(.text+0xe8d): undefined reference to `deflate'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXSocketOpenSSL.cpp.o): in function `ix::SocketOpenSSL::openSSLInitialize()':
IXSocketOpenSSL.cpp:(.text+0x20): undefined reference to `OPENSSL_init_ssl'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0x2d): undefined reference to `OPENSSL_init_ssl'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0x39): undefined reference to `OPENSSL_init_ssl'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXSocketOpenSSL.cpp.o): in function `ix::SocketOpenSSL::send(char*, unsigned long)':
IXSocketOpenSSL.cpp:(.text+0x93): undefined reference to `ERR_clear_error'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0xa2): undefined reference to `SSL_write'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0xb1): undefined reference to `SSL_get_error'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXSocketOpenSSL.cpp.o): in function `ix::SocketOpenSSL::recv(void*, unsigned long)':
IXSocketOpenSSL.cpp:(.text+0x157): undefined reference to `ERR_clear_error'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0x166): undefined reference to `SSL_read'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0x197): undefined reference to `SSL_get_error'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXSocketOpenSSL.cpp.o): in function `ix::SocketOpenSSL::getSSLError[abi:cxx11](int)':
IXSocketOpenSSL.cpp:(.text+0x82a): undefined reference to `SSL_get_error'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0x961): undefined reference to `ERR_get_error'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0xb11): undefined reference to `ERR_get_error'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0xb76): undefined reference to `ERR_error_string'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0xcae): undefined reference to `ERR_error_string'
/usr/bin/ld: /usr/local/lib/libixwebsocket.a(IXSocketOpenSSL.cpp.o): in function `ix::SocketOpenSSL::openSSLCreateContext(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&)':
IXSocketOpenSSL.cpp:(.text+0xd6f): undefined reference to `TLS_client_method'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0xd83): undefined reference to `SSL_CTX_new'
/usr/bin/ld: IXSocketOpenSSL.cpp:(.text+0xd9f): undefined reference to `SSL_CTX_ctrl'

[...]

Please help. Thanks

[bsergean]

You need to disable zlib and openssl (or any ssl library) if you aren't adding them to the linker line.

[bsergean]

Run cmake like this

USE_ZLIB=OFF
USE_TLS=OFF

It will limit capacities but will unblock you.