openssl/doc/crypto/BIO_new.pod
David Benjamin 04f6b0fd91 RT4660: BIO_METHODs should be const.
BIO_new, etc., don't need a non-const BIO_METHOD. This allows all the
built-in method tables to live in .rodata.

Reviewed-by: Richard Levitte <levitte@openssl.org>
2016-03-21 16:49:10 -04:00

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=pod
=head1 NAME
BIO_new, BIO_set, BIO_up_ref, BIO_free, BIO_vfree, BIO_free_all - BIO allocation and freeing functions
=head1 SYNOPSIS
#include <openssl/bio.h>
BIO * BIO_new(const BIO_METHOD *type);
int BIO_set(BIO *a,const BIO_METHOD *type);
int BIO_up_ref(BIO *a);
int BIO_free(BIO *a);
void BIO_vfree(BIO *a);
void BIO_free_all(BIO *a);
=head1 DESCRIPTION
The BIO_new() function returns a new BIO using method B<type>.
BIO_set() sets the method of an already existing BIO.
BIO_up_ref() increments the reference count associated with the BIO object.
BIO_free() frees up a single BIO, BIO_vfree() also frees up a single BIO
but it does not return a value.
If B<a> is NULL nothing is done.
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.
If B<a> is NULL nothing is done.
=head1 RETURN VALUES
BIO_new() returns a newly created BIO or NULL if the call fails.
BIO_set(), BIO_up_ref() and BIO_free() return 1 for success and 0 for failure.
BIO_free_all() and BIO_vfree() do not return values.
=head1 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() a single BIO has the same effect as calling BIO_free()
on it other than the discarded return value.
Normally the B<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_*();
=head1 EXAMPLE
Create a memory BIO:
BIO *mem = BIO_new(BIO_s_mem());
=head1 SEE ALSO
TBA