DH_size - get Diffie-Hellman prime size
#include <openssl/dh.h> int DH_size(DH *dh);
This function returns the Diffie-Hellman size in bytes. It can be used to determine how much memory must be allocated for the shared secret computed by DH_compute_key(). dh->p must not be NULL.
The size in bytes.
dh(3), DH_generate_key(3)
DH_size() is available in all versions of SSLeay and OpenSSL.