[#EVP_PKEY_CTX_ctrl_uint64]
= EVP_PKEY_CTX_ctrl_uint64
:mrdocs:

Send a control command with a uint64_t argument to a key context.

== Synopsis

Declared in `<openssl/evp.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
int
EVP_PKEY_CTX_ctrl_uint64(
    xref:EVP_PKEY_CTX.adoc[EVP_PKEY_CTX]* ctx,
    int keytype,
    int optype,
    int cmd,
    uint64_t value);
----

== Return Value

Positive value on success, or a non‐positive value on failure / unsupported command.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *ctx*
| Key context receiving the command.
| *keytype*
| Expected key type, or ‐1 to skip the type check.
| *optype*
| Expected operation type, or ‐1 to skip the operation check.
| *cmd*
| Algorithm‐specific control command.
| *value*
| 64‐bit integer argument for `cmd.`
|===


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