Kurento: Link library in OpenCV module

Question

I'm writing an OpenCV module to go with Kurento Media Server. I'm reading a file from an URL using lib curl.

The code I have is as follows:

#include<curl/curl.h>

size_t write_data(char *ptr, size_t size, size_t nmemb, void *userdata)
{
    vector<uchar> *stream = (vector<uchar>*)userdata;
    size_t count = size * nmemb;
    stream->insert(stream->end(), ptr, ptr + count);
    return count;
}

Mat curlImg(const char *img_url, int timeout=10)
{
    vector<uchar> stream;
    CURL *curl = curl_easy_init();
    curl_easy_setopt(curl, CURLOPT_URL, img_url);
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data); 
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &stream);
    curl_easy_setopt(curl, CURLOPT_TIMEOUT, timeout);
    curl_easy_perform(curl);
    curl_easy_cleanup(curl);
    return imdecode(stream, -1);
}

Mat image = curlImg(link);

Upon building it: I get the following warnings and the resultant package is not installed:

dpkg-shlibdeps: warning: symbol curl_easy_cleanup found in none of the libraries
dpkg-shlibdeps: warning: symbol curl_easy_perform found in none of the libraries
dpkg-shlibdeps: warning: symbol curl_easy_setopt found in none of the libraries
dpkg-shlibdeps: warning: symbol curl_easy_init found in none of the libraries

My guess is that there is a problem with linking the libraries in CMakeLists.txt

So how should I link these libraries?
Is target_link_libraries() the correct way? If so, what is the syntax?

Edit:

These are the ways I've tried so far.

1

SET(requiredlibs)

FIND_PACKAGE(CURL)
IF(CURL_FOUND)
    INCLUDE_DIRECTORIES(${CURL_INCLUDE_DIR})
    SET(requiredlibs ${requiredlibs} ${CURL_LIBRARIES} )
ELSE(CURL_FOUND)
    MESSAGE(FATAL_ERROR "Could not find the CURL library and development files.")
ENDIF(CURL_FOUND)

2

target_link_libraries (curl)

3

SET(${CURL_LIBRARIES} )

Answer 1

At the main folder project CMakeLists.txt where other requires are done, you need to add:

pkg_check_modules(CURL REQUIRED curl)

Then in folder src/server you need to modify CMakeLists.txt file as follows:

generate_code (
   MODELS ${CMAKE_CURRENT_SOURCE_DIR}/interface
   SERVER_STUB_DESTINATION ${CMAKE_CURRENT_SOURCE_DIR}/implementation/objects
   SERVER_IMPL_LIB_EXTRA_LIBRARIES ${CURL_LIBRARIES}
)