undefined reference to md5 [duplicate]

Question

#include <openssl/md5.h>
void mMD5(unsigned char * packet, int size) {

    unsigned char* res;

    MD5((unsigned char*)&packet, size, (unsigned char*)&res);

    for(int i=0; i<MD5_DIGEST_LENGTH; i++) {
        printf("%02x", res[i]);
    }
}

I get the error: undefined reference to MD5

Can anyone help me?

Answer 1

You need to link to the matching library. You should have a file called md5.lib or md5.a or something like that (depending on your OS), and add it to your linker command line (again, depending on your environment).