DH\_NEW(3ossl) OpenSSL DH\_NEW(3ossl)

# [NAME](#NAME)

DH\_new, DH\_free - allocate and free DH objects

# [SYNOPSIS](#SYNOPSIS)

```
 #include <openssl/dh.h>
```

The following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely by defining **OPENSSL\_API\_COMPAT** with a suitable version value, see [**openssl\_user\_macros**(7)](/man/os/openssl-4.0/openssl_user_macros.7):

```
 DH* DH_new(void);
 void DH_free(DH *dh);
```

# [DESCRIPTION](#DESCRIPTION)

**DH\_new()** allocates and initializes a **DH** structure.

**DH\_free()** frees the **DH** structure and its components. The values are erased before the memory is returned to the system. If **dh** is NULL nothing is done.

# [RETURN VALUES](#RETURN_VALUES)

If the allocation fails, **DH\_new()** returns **NULL** and sets an error code that can be obtained by [**ERR\_get\_error**(3)](/man/os/openssl-4.0/ERR_get_error.3). Otherwise it returns a pointer to the newly allocated structure.

**DH\_free()** returns no value.

# [SEE ALSO](#SEE_ALSO)

[**DH\_new**(3)](/man/os/openssl-4.0/DH_new.3), [**ERR\_get\_error**(3)](/man/os/openssl-4.0/ERR_get_error.3), [**DH\_generate\_parameters**(3)](/man/os/openssl-4.0/DH_generate_parameters.3), [**DH\_generate\_key**(3)](/man/os/openssl-4.0/DH_generate_key.3), [**EVP\_PKEY-DH**(7)](/man/os/openssl-4.0/EVP_PKEY-DH.7)

# [HISTORY](#HISTORY)

All of these functions were deprecated in OpenSSL 3.0.

For replacement see [**EVP\_PKEY-DH**(7)](/man/os/openssl-4.0/EVP_PKEY-DH.7).

# [COPYRIGHT](#COPYRIGHT)

Copyright 2000-2016 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 &lt;https://www.openssl.org/source/license.html&gt;.

2026-09-29 4.0.3

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Document: DH_free(3ossl) from openssl-4.0 4.0.3-r7 (Chainguard OS)