compilation error with httpConnect and httpConnectEncrypt

[Patrice]

Hello All
I have been trying to compile a simple project using cups API but I keep on getting the same error message. the code is as follow:

#include <stdio.h>
#include <iostream>

using namespace std;

int main( )
{
http_t* http = httpConnectEncrypt("156,145.12.0", 631, HTTP_ENCRYPT_ALWAYS);

return 0;

}

the error message is as follow: undefined reference to httpConnectEncrypt; when i change httpConnectEncrypt to httpConnect i get the same message.
Is there anything i should prior compilation of the program. please i really need your help.