NAME¶
BUF_MEM_new, BUF_MEM_free, BUF_MEM_grow, BUF_strdup - simple character arrays
structure
SYNOPSIS¶
#include <openssl/buffer.h>
BUF_MEM *BUF_MEM_new(void);
void BUF_MEM_free(BUF_MEM *a);
int BUF_MEM_grow(BUF_MEM *str, int len);
char * BUF_strdup(const char *str);
DESCRIPTION¶
The buffer library handles simple character arrays. Buffers are used for various
purposes in the library, most notably memory BIOs.
The library uses the BUF_MEM structure defined in buffer.h:
typedef struct buf_mem_st
{
int length; /* current number of bytes */
char *data;
int max; /* size of buffer */
} BUF_MEM;
length is the current size of the buffer in bytes,
max is the
amount of memory allocated to the buffer. There are three functions which
handle these and one "miscellaneous" function.
BUF_MEM_new() allocates a new buffer of zero size.
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_strdup() copies a null terminated string into a block of allocated
memory and returns a pointer to the allocated block. Unlike the standard C
library
strdup() this function uses
OPENSSL_malloc() and so
should be used in preference to the standard library
strdup() because
it can be used for memory leak checking or replacing the
malloc()
function.
The memory allocated from
BUF_strdup() should be freed up using the
OPENSSL_free() function.
RETURN VALUES¶
BUF_MEM_new() returns the buffer or NULL on error.
BUF_MEM_free() has no return value.
BUF_MEM_grow() returns zero on error or the new size (i.e.
len).
SEE ALSO¶
bio(3)
HISTORY¶
BUF_MEM_new(),
BUF_MEM_free() and
BUF_MEM_grow() are
available in all versions of SSLeay and OpenSSL.
BUF_strdup() was added
in SSLeay 0.8.