[#EVP_MAC_final]
= EVP_MAC_final
:mrdocs:

Finish a MAC computation and write the authentication tag to a buffer.

== Synopsis

Declared in `<openssl/evp.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
int
EVP_MAC_final(
    xref:EVP_MAC_CTX.adoc[EVP_MAC_CTX]* ctx,
    unsigned char* out,
    size_t* outl,
    size_t outsize);
----

== Return Value

1 on success, or 0 on error.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *ctx*
| MAC context previously updated with EVP_MAC_update().
| *out*
| Buffer that receives the MAC, or NULL to query the required size via `outl.`
| *outl*
| On success, receives the number of bytes written (or required if `out` is NULL).
| *outsize*
| Size of `out` in bytes when `out` is non‐NULL.
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#