Unable to link openssl libraries to CLion C program on windows with cygwin-CodePudding

I'm new to C programming, and I wanted to start a project for learning purposes. I am trying to open an ssl socket in C with clion on windows using cygwin. For the code I've been using this tutorial: https://aticleworld.com/ssl-server-client-using-openssl-in-c/

I've installed cygwin with those libs: make, gdb, gcc-g , libssl-dev

I don't see any compliation errors in the editor, but I can't run thr project. When I try to run it I get many errors of undefined during the linking phase:

undefined reference to `OPENSSL_init_crypto'
undefined reference to `OPENSSL_init_ssl'
undefined reference to `SSL_CTX_new'

and many more like it.

So I updated m cmake file to look like this:

cmake_minimum_required(VERSION 3.21)
project(ssl_example C)

set(CMAKE_C_STANDARD 99)
include_directories(/usr/include/openssl/)
link_libraries(openssl)
add_executable(ssl_example main.c)

and now I get this error-

FAILED: ssl_example.exe 
: && /usr/bin/gcc.exe -g -Wl,--enable-auto-import CMakeFiles/ssl_example.dir/main.c.o -o ssl_example.exe -Wl,--out-implib,libssl_example.dll.a -Wl,--major-image-version,0,--minor-image-version,0  -lopenssl  -lcrypto && :
/usr/lib/gcc/x86_64-pc-cygwin/11/../../../../x86_64-pc-cygwin/bin/ld: cannot find -lopenssl
collect2: error: ld returned 1 exit status

CodePudding user response：

OPENSSL_init_crypto belongs to libcrypto

$ cd /usr/lib

$ grep OPENSSL_init_crypto  *.dll.a
grep: libcrypto.dll.a: binary file matches

$ nm libcrypto.dll.a |grep " T " |grep OPENSSL_init
0000000000000000 T OPENSSL_init_crypto
0000000000000000 T OPENSSL_init

while the other two to libssl

$ grep OPENSSL_init_ssl  *.dll.a
grep: libssl.dll.a: binary file matches

$ nm libssl.dll.a |grep " T " |grep OPENSSL_init_ssl
0000000000000000 T OPENSSL_init_ssl

$ grep SSL_CTX_new *.dll.a
grep: libQtNetwork.dll.a: binary file matches
grep: libssl.dll.a: binary file matches

nm libssl.dll.a |grep " T " |grep SSL_CTX_new
0000000000000000 T SSL_CTX_new

so you need to link versus both libssl and libcrypto

CodePudding user response：

The library you must link to is called "libssl" not "openssl". In the linking must appear as '-lssl', not '-lopenssl'