ld: library not found for -lssl collect2: ld returned 1 exit status

i try to use libcurl.a library in my app project. I have add that lib on framework list, and now i want to called some headers from that lib. The headers are :

#include "curl.h"
#include "types.h"
#include "easy.h"

but, when i try to build my project, xcode give me 1 error, that is :

ld: library not found for -lssl 
collect2: ld returned 1 exit status 
Command /Develop开发者_Python百科er/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 failed with exit code 1

i dont understand about this error, can somebody help me?? Thank you

Risma

iOS appears to include neither libcurl nor libssl. Unless you've built these yourself and are statically linking them into your application, you will not be able to use them: the library is not found because it is not present. If you are statically linking them, you must also acknowledge that your software includes them somewhere in your application to comply with their license terms.