[cs631apue] EVP_EncryptFinal_ex

[yluo4]

Hi,I have a couple of questions.
First,about  EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char 
*out,int *outl, unsigned char *in, int inl), does it encrypt 'inl' long 
data every time and when the length of the data pointed by 'in' is less 
than 'inl', then invoke  EVP_EncryptFinal_ex?
Another question, I have include <openssl/evp.h>, but when I compile my 
program, it gives the warms:
bfed.c:(.text+0xf5): undefined reference to `EVP_CIPHER_CTX_init'
bfed.c:(.text+0xfa): undefined reference to `EVP_bf_cbc'
bfed.c:(.text+0x128): undefined reference to `EVP_EncryptInit_ex'
bfed.c:(.text+0x15a): undefined reference to `EVP_EncryptUpdate'
bfed.c:(.text+0x261): undefined reference to `EVP_EncryptFinal_ex'
I can't figure it out.
  Thank you!
   Yulong