[#BN_is_prime_ex]
= BN_is_prime_ex
:mrdocs:

Test whether `p` is prime using Miller‐Rabin (deprecated; prefer BN_check_prime).

== Synopsis

Declared in `<openssl/bn.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[deprecated]]
int
BN_is_prime_ex(
    xref:BIGNUM.adoc[BIGNUM] const* p,
    int nchecks,
    xref:BN_CTX.adoc[BN_CTX]* ctx,
    xref:BN_GENCB.adoc[BN_GENCB]* cb);
----

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

1 if probably prime, 0 if composite, or ‐1 on error.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *p*
| Candidate integer.
| *nchecks*
| Number of Miller‐Rabin rounds, or BN_prime_checks for a default.
| *ctx*
| Optional BN_CTX, or NULL to allocate internally.
| *cb*
| Optional progress callback, or NULL.
|===


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