.. _pqspp_free_memory:


====================
PQSPP_free_memory
====================


Description
------------

`PQSPP_free_memory` frees up any memory that was allocated but will not be in used anymore. 


Syntax
--------

.. code-block:: c

    int PQSPP_free_memory(
        uint8_t*        mem, 
    );

Parameters
------------
- `mem`
A pointer to a memory address that needs to be freed.

Return value
--------------

+-------------+----------------------------+
| Return code | Description                |   
+=============+============================+
| PQSPP_OK    | The function was successful|
+-------------+----------------------------+

Anything other than OK is an error.

Code example
------------------

.. code-block:: c

    #include "pqspp.h"
    #include "sha256.h"

    #include <stdio.h>
    #include <stdlib.h>

    int main() 
    {

        // PQSPP_keygen
        /*
        uint8_t *sk = NULL;
        uint8_t *pk = NULL;
        int pk_len = -1;

        int ret = PQSPP_keygen(&sk, &pk, &pk_len);
        if (ret != PQSPP_OK) {
            printf("Error in keygen: %d\n", ret);
            return -1;
        }
        printf(
            "Generated a secret key and a public key (DER encoded of length %d)!\n",
            pk_len);
        */

        // PQSPP_sign_digest
        /*
        // message digest
        uint8_t message[4] = {0x01, 0x02, 0x03, 0x04};
        unsigned char hash[32];
        SHA256_CTX ctx;

        // hash the message 
        sha256_init(&ctx);
        sha256_update(&ctx,message,sizeof(message));
        sha256_final(&ctx,hash);

        uint8_t *ec_sig = NULL;
        int ec_sig_len = -1;
        uint8_t *pip = NULL;
        int pip_len = -1;

        ret =
            PQSPP_sign_digest(sk, hash,sizeof(hash), &ec_sig, &ec_sig_len, &pip, &pip_len);
        if (ret != PQSPP_OK) {
            printf("Error in sign: %d\n", ret);
            PQSPP_free_memory(sk);
            PQSPP_free_memory(pk);
            return -2;
        }
        printf("Signed a message; got a pq_proof of size %d bytes\n", pip_len);
        */

        // PQSPP_verify_digest
        /*
        ret = PQSPP_verify_digest(pk, pk_len, hash, sizeof(hash), ec_sig, ec_sig_len, pip,
        pip_len);
        if (ret != PQSPP_OK) {
            printf("Error in verify: %d\n", ret);
            PQSPP_free_memory(sk);
            PQSPP_free_memory(pk);
            PQSPP_free_memory(ec_sig);
            PQSPP_free_memory(pip);
            return -3;
        }

        printf("Successfully verified the signature and the preimage proof!\n");
        */

        // PQSPP_free_memory
        PQSPP_free_memory(sk);
        PQSPP_free_memory(pk);
        PQSPP_free_memory(ec_sig);
        PQSPP_free_memory(pip);

        return 0;
    }