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);
#define
BIO_set_fd(b,fd,c) BIO_int_ctrl(b,BIO_C_SET_FD,c,fd)
#define BIO_get_fd(b,c) BIO_ctrl(b,BIO_C_GET_FD,0,(char
*)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 c.
BIO_get_fd()
places the file descriptor in c if it is not
NULL, it also returns the file descriptor. If
c is not NULL, it should be of
type int *.
BIO_new_fd()
returns a file descriptor BIO using fd and
close_flag.
NOTES
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.
RETURN VALUES
BIO_s_fd() returns the file descriptor BIO
method.
BIO_reset(3) returns zero for success and -1 if an error occurred. BIO_seek(3) and BIO_tell(3) return the current file position or -1 if an error occurred. These values reflect the underlying lseek(2) behaviour.
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.
EXAMPLE
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);