buffer(3)buffer(3)NAME
buffer, 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;
The 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.
The BUF_MEM_new() function allocates a new buffer of zero size.
The BUF_MEM_free() function frees up an already existing buffer. The
data is zeroed before freeing up in case the buffer contains sensitive
data.
The BUF_MEM_grow() function changes the size of an already existing
buffer to len. Any data already in the buffer is preserved if it
increases in size.
The BUF_strdup() function 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_mal‐
loc(). It should be used in preference to the standard library strdup()
because it can be used for memory leak checking or replacing the mal‐
loc() function.
The memory allocated from the BUF_strdup() function should be freed up
using the OPENSSL_free() function.
RETURN VALUES
The BUF_MEM_new() function returns the buffer or NULL on error.
The BUF_MEM_free() function has no return value.
The BUF_MEM_grow() function returns zero on error or the new size (i.e.
len).
HISTORY
The BUF_MEM_new(), BUF_MEM_free(), and BUF_MEM_grow() functions are
available in all versions of SSLeay and OpenSSL. The BUF_strdup() func‐
tion was added in SSLeay 0.8.
SEE ALSO
Function: bio(3)buffer(3)