- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- SEE ALSO
- HISTORY
- COPYRIGHT

# NAME

BUF_MEM_new, BUF_MEM_new_ex, BUF_MEM_free, BUF_MEM_grow, BUF_MEM_grow_clean, BUF_reverse - simple character array structure

# SYNOPSIS

     #include <openssl/buffer.h>

     BUF_MEM *BUF_MEM_new(void);

     BUF_MEM *BUF_MEM_new_ex(unsigned long flags);

     void BUF_MEM_free(BUF_MEM *a);

     int BUF_MEM_grow(BUF_MEM *str, int len);
     size_t BUF_MEM_grow_clean(BUF_MEM *str, size_t len);

     void BUF_reverse(unsigned char *out, const unsigned char *in, size_t size);

# DESCRIPTION

The buffer library handles simple character arrays. Buffers are used for various purposes in the library, most notably memory BIOs.

`BUF_MEM_new()` allocates a new buffer of zero size.

`BUF_MEM_new_ex()` allocates a buffer with the specified flags. The flag BUF_MEM_FLAG_SECURE specifies that the data pointer should be allocated on the secure heap; see CRYPTO_secure_malloc(3).

`BUF_MEM_free()` frees up an already existing buffer. The data is zeroed before freeing up in case the buffer contains sensitive data.

`BUF_MEM_grow()` changes the size of an already existing buffer to len. Any data already in the buffer is preserved if it increases in size.

`BUF_MEM_grow_clean()` is similar to `BUF_MEM_grow()` but it sets any free'd or additionally-allocated memory to zero.

`BUF_reverse()` reverses size bytes at in into out. If in is NULL, the array is reversed in-place.

# RETURN VALUES

`BUF_MEM_new()` returns the buffer or NULL on error.

`BUF_MEM_free()` has no return value.

`BUF_MEM_grow()` and `BUF_MEM_grow_clean()` return zero on error or the new size (i.e., len).

# SEE ALSO

bio(7), CRYPTO_secure_malloc(3).

# HISTORY

The `BUF_MEM_new_ex()` function was added in OpenSSL 1.1.0.

# COPYRIGHT

Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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.