/xlv3/openssl/0.9.7e-sgipl1/work/0.9.7e-sgipl1/openssl-
0.9.7e/doc/crypto
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buffer(3) 19/Sep/2000 (0.9.7e) buffer(3)
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.
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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.
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