[#EVP_DigestVerifyInit_ex]
= EVP_DigestVerifyInit_ex
:mrdocs:

Initialize a digest‐verify operation with an explicit digest name and library context.

== Synopsis

Declared in `<openssl/evp.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
int
EVP_DigestVerifyInit_ex(
    xref:EVP_MD_CTX.adoc[EVP_MD_CTX]* ctx,
    xref:EVP_PKEY_CTX.adoc[EVP_PKEY_CTX]** pctx,
    char const* mdname,
    xref:OSSL_LIB_CTX.adoc[OSSL_LIB_CTX]* libctx,
    char const* props,
    xref:EVP_PKEY.adoc[EVP_PKEY]* pkey,
    xref:OSSL_PARAM.adoc[OSSL_PARAM] const params[]);
----

== Return Value

1 on success, or 0 on failure.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *ctx*
| Digest context to initialize for verification.
| *pctx*
| Optional receiver for the internal EVP_PKEY_CTX, or NULL.
| *mdname*
| Digest algorithm name (for example "SHA256"), or NULL to use the key default.
| *libctx*
| Library context for algorithm fetches, or NULL for the default.
| *props*
| Property query string for fetches, or NULL.
| *pkey*
| Public key used to verify the signature.
| *params*
| Optional OSSL_PARAM array of algorithm parameters, or NULL.
|===


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