BIO_s_fd(3)BIO_s_fd(3)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
The BIO_s_fd() function returns the file descriptor BIO method. This is
a wrapper around the platform's file descriptor routines, such as
read() and write().
The BIO_read() and BIO_write() functions read or write the underlying
descriptor. BIO_puts() is supported, but BIO_gets() is not.
If the close flag is set then then close() is called on the underlying
file descriptor when the BIO is freed.
The BIO_reset() function attempts to change the file pointer to the
start of file using lseek(fd, 0, 0).
The BIO_seek() function sets the file pointer to position ofs from
start of file using lseek(fd, ofs, 0).
The BIO_tell() function returns the current file position by calling
lseek(fd, 0, 1).
The BIO_set_fd() function sets the file descriptor of BIO b to fd and
the close flag to c.
The BIO_get_fd() function 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 *).
The BIO_new_fd() function returns a file descriptor BIO using fd and
close_flag.
NOTES
The behavior of the BIO_read() and BIO_write() functions depends on the
behavior of the platform's read() and write() calls on the descriptor.
If the underlying file descriptor is in a nonblocking mode then the
BIO will behave in the manner described in the BIO_read(3) and
BIO_should_retry(3) reference pages.
File descriptor BIOs should not be used for socket I/O. Use socket BIOs
instead.
RETURN VALUESBIO_s_fd() returns the file descriptor BIO method.
BIO_reset() returns zero for success and -1 if an error occurred.
BIO_seek() and BIO_tell() return the current file position or -1 is an
error occurred. These values reflect the underlying lseek() behavior.
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 is 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
Functions: BIO_seek(3), BIO_tell(3), BIO_reset(3), BIO_read(3),
BIO_write(3), BIO_puts(3), BIO_gets(3), BIO_printf(3),
BIO_set_close(3), BIO_get_close(3)BIO_s_fd(3)