- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUES
- NOTES
- EXAMPLE
- SEE ALSO

# 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(), `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()` 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_*();

# EXAMPLE

Create a memory BIO:

     BIO *mem = BIO_new(BIO_s_mem());

# SEE ALSO

TBA