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.

Linux 6.8.2-arch2-1              July 27, 2023             Linux 6.8.2-arch2-1