[#HMAC_Update]
= HMAC_Update
:mrdocs:

Absorb more message bytes into an HMAC context (deprecated; prefer EVP_MAC_update).

== Synopsis

Declared in `<openssl/hmac.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[deprecated]]
int
HMAC_Update(
    xref:HMAC_CTX.adoc[HMAC_CTX]* ctx,
    unsigned char const* data,
    size_t len);
----

[WARNING]
====
https://en.cppreference.com/cpp/language/attributes/deprecated[Deprecated^]. Use of this entity is allowed but discouraged.
====
== Return Value

1 on success, or 0 on failure.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *ctx*
| HMAC context initialized with HMAC_Init_ex().
| *data*
| Next chunk of message bytes.
| *len*
| Number of bytes at `data.`
|===


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