/usr/man/cat.3/BIO_get_fd.3

BIO_s_fd(3)                  OpenSSL                  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

     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() and BIO_write() 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.

     BIO_reset() attempts to change the file pointer to the start
     of file using lseek(fd, 0, 0).

     BIO_seek() sets the file pointer to position ofs from start
     of file using lseek(fd, ofs, 0).

     BIO_tell() 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() and BIO_write() 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(3) and BIO_should_retry(3) manual
     pages.

1.0.2t               Last change: 2019-09-10                    1

BIO_s_fd(3)                  OpenSSL                  BIO_s_fd(3)

     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() returns zero for success and -1 if an error
     occurred.  BIO_seek() and BIO_tell() return the current file
     position or -1 if an error occurred. These values reflect
     the underlying lseek() 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 is 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);

SEE ALSO

     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)

1.0.2t               Last change: 2019-09-10                    2

See also BIO_new_fd(3)
See also BIO_s_fd(3)
See also BIO_set_fd(3)