NAME
BIO_s_fd
,
BIO_set_fd
, BIO_get_fd
,
BIO_new_fd
—
file descriptor BIO
SYNOPSIS
#include
<openssl/bio.h>
BIO_METHOD *
BIO_s_fd
(void);
long
BIO_set_fd
(BIO *b,
int fd, long close_flag);
long
BIO_get_fd
(BIO *b,
int *c);
BIO *
BIO_new_fd
(int fd,
int close_flag);
DESCRIPTION
BIO_s_fd
()
returns the file descriptor BIO method. This is a wrapper around the
platform's file descriptor routines such as
read(2) and
write(2).
BIO_read(3) and BIO_write(3) read or write the underlying descriptor. BIO_puts(3) is supported but BIO_gets(3) is not.
If the close flag is set, close(2) is called on the underlying file descriptor when the BIO is freed.
BIO_reset(3) attempts to set the file pointer to the start of
the file using
lseek
(fd,
0, 0).
BIO_seek(3) sets the file pointer to position
ofs from start of file using
lseek
(fd,
ofs, 0).
BIO_tell(3) returns the current file position by calling
lseek
(fd,
0, 1).
BIO_set_fd
()
sets the file descriptor of BIO
b to fd and the close flag to
close_flag. It is currently implemented as a
macro.
BIO_get_fd
()
places the file descriptor in c if it is not
NULL
and also returns the file descriptor. It is
currently implemented as a macro.
BIO_new_fd
()
returns a file descriptor BIO using fd and
close_flag.
The behaviour of BIO_read(3) and BIO_write(3) depends on the behavior of the platform's read(2) and write(2) calls on the descriptor. If the underlying file descriptor is in a non-blocking mode, then the BIO will behave in the manner described in the BIO_read(3) and BIO_should_retry(3) manual pages.
File descriptor BIOs should not be used for socket I/O. Use socket BIOs instead.
BIO_set_fd
()
and BIO_get_fd
() are implemented as macros.
RETURN VALUES
BIO_s_fd
() returns the file descriptor BIO
method.
BIO_set_fd
() always returns 1.
BIO_get_fd
() returns the file descriptor
or -1 if the BIO has not been initialized.
BIO_new_fd
() returns the newly allocated
BIO or NULL
if an error
occurred.
EXAMPLES
This is a file descriptor BIO version of "Hello World":
BIO *out; out = BIO_new_fd(fileno(stdout), BIO_NOCLOSE); BIO_printf(out, "Hello World\n"); BIO_free(out);
SEE ALSO
HISTORY
These functions appeared in SSLeay 0.8.1b or earlier and have been available since OpenBSD 2.4.