[#EVP_PKEY_meth_set_digest_custom]
= EVP_PKEY_meth_set_digest_custom
:mrdocs:

Set the digest_custom callback on a custom EVP_PKEY_METHOD (deprecated).

== Synopsis

Declared in `<openssl/evp.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[deprecated]]
void
EVP_PKEY_meth_set_digest_custom(
    xref:EVP_PKEY_METHOD.adoc[EVP_PKEY_METHOD]* pmeth,
    int(* digest_custom)(xref:EVP_PKEY_CTX.adoc[EVP_PKEY_CTX]*, xref:EVP_MD_CTX.adoc[EVP_MD_CTX]*));
----

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

[cols="1,4"]
|===
| Name| Description
| *pmeth*
| Method table to update.
| *digest_custom*
| Callback invoked by EVP_DigestSignInit()/VerifyInit() to hash algorithm‐specific prefix data (for example SM2), or NULL.
|===


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