Cryptography and SSL/TLS Toolkit



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


 #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);


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.


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).


bio(7), CRYPTO_secure_malloc(3).


The BUF_MEM_new_ex() function was added in OpenSSL 1.1.0.

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