BUF_MEM_NEW(3) Library Functions Manual BUF_MEM_NEW(3)
NAME
BUF_MEM_new, BUF_MEM_free, BUF_MEM_grow, BUF_MEM_grow_clean — 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, size_t len);
int
BUF_MEM_grow_clean(BUF_MEM *str, size_t len);
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
{
|
size_t length; |
/* current number of bytes */ |
|||
|
char *data; |
||||
|
size_t 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. If a is a NULL pointer, no action occurs.
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 freed or additionally allocated memory to zero.
RETURN VALUES
BUF_MEM_new() returns the buffer or NULL on error.
BUF_MEM_grow() and BUF_MEM_grow_clean() return zero on error or the new size (i.e. len).
SEE ALSO
BIO_new(3), BIO_s_mem(3)
HISTORY
BUF_MEM_new(), BUF_MEM_free(), and BUF_MEM_grow() first appeared in SSLeay 0.6.0. All these functions have been available since OpenBSD 2.4.
BUF_MEM_grow_clean() first appeared in OpenSSL 0.9.7 and has been available since OpenBSD 3.2. GNU July 27, 2023 BUF_MEM_NEW(3)