---
name: "OSSL_PARAM_dup"
section: "3ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/OSSL_PARAM_dup"
---

# OSSL\_PARAM\_dup(3ssl)

OSSL\_PARAM array copy functions

## NAME

OSSL\_PARAM\_dup, OSSL\_PARAM\_merge, OSSL\_PARAM\_free - OSSL\_PARAM array copy functions

## SYNOPSIS

```
 #include <openssl/params.h>
 OSSL_PARAM *OSSL_PARAM_dup(const OSSL_PARAM *params);
 OSSL_PARAM *OSSL_PARAM_merge(const OSSL_PARAM *params, const OSSL_PARAM *params1);
 void OSSL_PARAM_free(OSSL_PARAM *params);
```

## DESCRIPTION

Algorithm parameters can be exported/imported from/to providers using arrays of **OSSL\_PARAM**(3). The following utility functions allow the parameters to be duplicated and merged with other **OSSL\_PARAM**(3) to assist in this process.

**OSSL\_PARAM\_dup()** duplicates the parameter array *params*. This function does a deep copy of the data.

**OSSL\_PARAM\_merge()** merges the parameter arrays *params* and *params1* into a new parameter array. If *params* and *params1* contain values with the same 'key' then the value from *params1* will replace the *param* value. This function does a shallow copy of the parameters. Either *params* or *params1* may be NULL. The behaviour of the merge is unpredictable if *params* and *params1* contain the same key, and there are multiple entries within either array that have the same key.

**OSSL\_PARAM\_free()** frees the parameter array *params* that was created using **OSSL\_PARAM\_dup()**, **OSSL\_PARAM\_merge()** or **OSSL\_PARAM\_BLD\_to\_param()**. If the argument to **OSSL\_PARAM\_free()** is NULL, nothing is done.

## RETURN VALUES

The functions **OSSL\_PARAM\_dup()** and **OSSL\_PARAM\_merge()** return a newly allocated **OSSL\_PARAM**(3) array, or NULL if there was an error. If both parameters are NULL\
  then NULL is returned.

## SEE ALSO

**OSSL\_PARAM**(3), **OSSL\_PARAM\_BLD**(3)

## HISTORY

The functions were added in OpenSSL 3.0.

## COPYRIGHT

Copyright 2021-2024 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\>.