Function EVP_PKEY_decapsulate 

pub unsafe extern "C" fn EVP_PKEY_decapsulate(
    ctx: *mut EVP_PKEY_CTX,
    out_secret: *mut u8,
    out_secret_len: *mut usize,
    ciphertext: *const u8,
    ciphertext_len: usize,
) -> c_int