NAME

       OSSL_DISPATCH - OpenSSL Core type to define a dispatchable function table

SYNOPSIS

        #include <openssl/core.h>

        typedef struct ossl_dispatch_st OSSL_DISPATCH;
        struct ossl_dispatch_st {
            int function_id;
            void (*function)(void);
        };

DESCRIPTION

       This type is a tuple of function identity and function pointer.  Arrays of this type are
       passed between the OpenSSL libraries and the providers to describe what functionality one
       side provides to the other.

       Arrays of this type must be terminated with a tuple having function identity zero and
       function pointer NULL.

   OSSL_DISPATCH fields
       function_id
           OpenSSL defined function identity of the implemented function.

       function
           Pointer to the implemented function itself.  Despite the generic definition of this
           field, the implemented function it points to must have a function signature that
           corresponds to the function_id

       Available function identities and corresponding function signatures are defined in
       openssl-core_dispatch.h(7).  Furthermore, the chosen function identities and associated
       function signature must be chosen specifically for the operation that it's intended for,
       as determined by the intended OSSL_ALGORITHM(3) array.

       Any function identity not recognised by the recipient of this type will be ignored.  This
       ensures that providers built with one OpenSSL version in mind will work together with any
       other OpenSSL version that supports this mechanism.

SEE ALSO

       crypto(7), openssl-core_dispatch.h(7), OSSL_ALGORITHM(3)

HISTORY

       OSSL_DISPATCH was added in OpenSSL 3.0.

COPYRIGHT

       Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.