
<p>EVP_MAC_get0_name() returns a name of the MAC, or NULL on error.</p>

<p>EVP_MAC_get0_provider() returns a pointer to the provider for the MAC, or NULL on error.</p>

<p>EVP_MAC_CTX_new() and EVP_MAC_CTX_dup() return a pointer to a newly created EVP_MAC_CTX, or NULL if allocation failed.</p>

<p>EVP_MAC_CTX_free() returns nothing at all.</p>

<p>EVP_MAC_CTX_get_params() and EVP_MAC_CTX_set_params() return 1 on success, 0 on error.</p>

<p>EVP_Q_mac() returns a pointer to the computed MAC value, or NULL 