buffer(3)                           OpenSSL                          buffer(3)



NAME
       BUF_MEM_new, BUF_MEM_free, BUF_MEM_grow, BUF_strdup - simple character
       arrays structure

LIBRARY
       libcrypto, -lcrypto

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 stan-
       dard 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() func-
       tion.

       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
       openssl_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.



0.9.9-dev                         2001-04-12                         buffer(3)
