BIO_s_fd, BIO_set_fd, BIO_get_fd, BIO_new_fd - file descriptor BIO
#include <openssl/bio.h>
const BIO_METHOD *BIO_s_fd(void);
int BIO_set_fd(BIO *b, int fd, int c);
int BIO_get_fd(BIO *b, int *c);
BIO *BIO_new_fd(int fd, int close_flag);
BIO_s_fd() returns the file descriptor BIO method. This is a wrapper
round the platforms file descriptor routines such as
read() and
write().
BIO_read_ex() and
BIO_write_ex() read or write the underlying
descriptor.
BIO_puts() is supported but
BIO_gets() is not.
If the close flag is set then
close() is called on the underlying file
descriptor when the BIO is freed.
BIO_reset() attempts to change the file pointer to the start of file such
as by using
lseek(fd, 0, 0).
BIO_seek() sets the file pointer to position
ofs from start of
file such as by using
lseek(fd, ofs, 0).
BIO_tell() returns the current file position such as 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 of BIO
b in
c if it
is not NULL. It also returns the file descriptor.
BIO_new_fd() returns a file descriptor BIO using
fd and
close_flag.
The behaviour of
BIO_read_ex() and
BIO_write_ex() depends on the
behavior of the platforms
read() and
write() 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_ex(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.
BIO_s_fd() returns the file descriptor BIO method.
BIO_set_fd() returns 1 on success or <=0 for failure.
BIO_get_fd() returns the file descriptor or -1 if the BIO has not been
initialized. It also returns zero and negative values if other error occurs.
BIO_new_fd() returns the newly allocated BIO or NULL is an error
occurred.
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);
BIO_seek(3),
BIO_tell(3),
BIO_reset(3),
BIO_read_ex(3),
BIO_write_ex(3),
BIO_puts(3),
BIO_gets(3),
BIO_printf(3),
BIO_set_close(3),
BIO_get_close(3)
Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy in the
file LICENSE in the source distribution or at
<
https://www.openssl.org/source/license.html>.