NAME
BIO_new, BIO_set,
BIO_free, BIO_vfree,
BIO_free_all —
BIO allocation and freeing
functions
SYNOPSIS
#include
<openssl/bio.h>
BIO *
BIO_new(BIO_METHOD *type);
int
BIO_set(BIO *a,
BIO_METHOD *type);
int
BIO_free(BIO *a);
void
BIO_vfree(BIO *a);
void
BIO_free_all(BIO *a);
DESCRIPTION
The
BIO_new()
function returns a new BIO using method type.
BIO_set()
sets the method of an already existing BIO.
BIO_free()
frees up a single BIO,
BIO_vfree()
also frees up a single BIO, but it does not return a value. Calling
BIO_free() may also have some effect on the
underlying I/O structure, for example it may close the file being referred
to under certain circumstances. For more details see the individual
BIO_METHOD descriptions.
BIO_free_all()
frees up an entire BIO chain. It does not halt if an error occurs freeing up
an individual BIO in the chain.
RETURN VALUES
BIO_new() returns a newly created BIO or
NULL if the call fails.
BIO_set() and
BIO_free() return 1 for success and 0 for
failure.
BIO_free_all() and
BIO_vfree() do not return values.
NOTES
Some BIOs (such as memory BIOs) can be used immediately after
calling
BIO_new().
Others (such as file BIOs) need some additional initialization, and
frequently a utility function exists to create and initialize such BIOs.
If
BIO_free()
is called on a BIO chain, it will only free one BIO, resulting in a memory
leak.
Calling
BIO_free_all()
on a single BIO has the same effect as calling
BIO_free() on it other than the discarded return
value.
Normally the type argument is
supplied by a function which returns a pointer to a
BIO_METHOD. There is a naming convention for such
functions: a source/sink BIO is normally called
BIO_s_*()
and a filter BIO
BIO_f_*().
EXAMPLES
Create a memory BIO:
BIO *mem =
BIO_new(BIO_s_mem());